He said: "Many of those who will lose their leave to remain are entirely dependent on the welfare state and will leave voluntarily upon losing access to benefits.
"Those that don't will be subject to immigration enforcement as part of our mass deportation programme."
The announcement marks a new campaign by Reform against the "Boriswave" of 3.8 million people who moved to the UK after Brexit under more relaxed rules introduced by Boris Johnson's Government.
Farage will warn that "Boriswave" migrants will become eligible for indefinite leave to remain (ILR) in January, giving them "catastrophic" lifetime access to the NHS and welfare benefits.
He will pledge to abolish ILR entirely within 100 days of a Reform Government winning office, forcing economic migrants to apply for visas with stricter conditions.
The Government does not publish figures on the number of migrants with ILR status, but there were a further 163,353 grants of settlement in the year to June 2025 - an increase of 18% on the previous year. The total figure could be over one million.
Prime Minister Sir Keir Starmer faces growing pressure over his "one in, one out" migration deal with France, under which only three people have so far been deported.
He has promised to bring down net migration among legal arrivals to the UK, which fell last year to 431,000 but remains significantly higher than pre-Brexit levels.
The announcement follows one of Britain's largest ever right-wing rallies, in which around 100,000 protesters, led by Tommy Robinson, marched in London, chanting anti-migration slogans.
Currently, foreign nationals can apply for indefinite leave to remain after spending five years in the UK, and convert their settled status to citizenship after a further 12 months.
But under Reform's plans, migrants would be forced to reapply for their visas every five years, meet a higher salary threshold than the current level of £35,800 ($82,342) for skilled workers, and wait seven years before applying for a British passport.
They would also be required to prove they are fluent in English to a professional standard and have "good character" and a clean criminal record. Any applicant who has spent more than 90 days outside the UK or claimed benefits would be banned from remaining in the country.
Unlike the current system, the new worker visa would give settled migrants no access to the welfare state or free services from the NHS, which Reform says would save "well in excess of £230bn" over the lifetime of the average claimant.
Yusuf said half of Boriswave migrants and their dependents did not work, setting up a "financial disaster" for the UK when 800,000 people become eligible to claim benefits next year.
Declaring that the "era of cheap foreign labour is over", he added: "Our nation is proud, resourceful, and resilient, but we have been suffocated by a political class that continues to betray the British people.
"For too long, the Tories and Labour have rolled out the red carpet for mass unskilled immigration, turning Britain into a food bank for the world."
The policy echoes the latest restrictions placed on economic migration in the US by Donald Trump, who has announced plans to charge US$100,000 ($170,000) for skilled worker visa applications.
Yusuf has been placed in charge of preparing Reform's policy agenda before the next election, which the party believes could take place as soon as 2027.
Reform is currently leading both Labour and the Conservatives by more than 12 points in the opinion polls, and looks set to pick up further seats in local and devolved government next May.
The party's immigration policy launch follows criticism of the rules on economic migration under Johnson, including by Kemi Badenoch, the Tory leader.
The first statistics on the nationality of benefit claimants, published by the Home Office in July, showed between 15 and 17% of those who receive Universal Credit are migrants.
Labour has said it plans to "toughen up the system" by doubling the length of time a person must live in the UK before they can be granted indefinite leave to remain, although the rules have not yet been changed.
Reform's policy is likely to meet criticism from some businesses that rely on foreign workers for inexpensive labour.
The party says it would introduce a new "Acute Skills Shortage Visa" to quickly process migrants to work in sectors with major job shortages, but any employer sponsoring one of the visas must pay for a British worker to be trained in the same skills.
Wealthy foreign entrepreneurs would also be allowed to settle in the UK, and would be given new "golden" visas with requirements to invest in the British economy.
A Government spokesman said: "People here illegally rightly do not get anything from our benefits system.
"Foreign nationals usually have to wait five years to claim Universal Credit and we're looking at increasing this to 10 years.
"We inherited a broken welfare system and spiralling benefits bill. That's why we're taking action and reforming the system and have seen the proportion of Universal Credit payments to foreign nationals fall since last July."
By Zia Yusuf
Britain stands on the brink of fiscal disaster. The biggest catastrophe the Tories unleashed on Britain is yet to explode. The "Boriswave" - the millions of unskilled, non-EU migrants they imported - will cost the taxpayer at least £234b, according to the Centre for Policy Studies.
Half the Boriswave migrants do not work, and never will. At least 800,000 of them will shortly qualify for Indefinite Leave to Remain (ILR), which gives them lifetime access to our welfare state. This is a scam on the British people perpetrated by the Tory party. Reform will avert this crisis. We will abolish ILR altogether - including rescinding it retrospectively - and close all loopholes to ensure only UK citizens receive welfare or social housing.
Britain stands at a crossroads. Our nation is proud, resourceful, and resilient, but we have been suffocated by a political class that continues to betray the British people. For too long, the Tories and Labour have rolled out the red carpet for mass unskilled immigration, turning Britain into a food bank for the world
Britain is going broke. Last year, the British taxpayer spent £266bn on welfare. £52bn of that went on Universal Credit. Of that, almost £9bn went to foreign nationals. One in six people on Universal Credit is a foreign national. The Tories and Labour have turned Britain into a food bank for the world, at the expense of our own people.
This is about to become catastrophic. Between 2026 and 2030, thanks to the Boriswave, 800,000 new migrants are estimated to get ILR. About half of all of them will never work, ever. And yet, every single one of them will have full access to our bloated welfare state for life.
The Boriswave is not made up of scientists, entrepreneurs, and doctors. Sixty per cent of the Boriswave are low-skilled immigrants who, once they've gained ILR, will bring further family members and dependants with them.
For example, in 2023, the UK Department for Health and Social Care (DHSC) estimated it would issue 6000 social care visas. The real number ended up being 348,000 - a staggering 58 times the government estimate. Remarkably, 55% of those were dependants.
Overall, the Boriswave allowed 3.8 million new people into the country on long-term visas (96% to non-EU nationals), of which two million are on the path to ILR. The Boriswave will start to be eligible for ILR from January 1, 2026. Estimates suggest that at least 800,000 of these individuals will be granted ILR under current rules at a total lifetime cost to the British taxpayer (likely underestimated) of £234b. That's four times our entire defence budget, double our education budget, and 12 times our Police budget.
Our solution to this problem is to abolish ILR completely. That means no new awards and those who currently hold it will have it rescinded. We will replace it with a five-year renewable work visa, with a vastly higher qualifying salary, much reduced ability to bring dependents and a much higher required standard of English. Crucially, this visa will give holders no access to welfare.
These changes will lead to hundreds of thousands of people having to apply and ultimately losing their settled status in the UK, which will be done on a staggered and orderly basis to allow businesses to train British workers to replace them. Many of those who will lose their leave to remain are entirely dependent on the welfare state and will leave voluntarily upon losing access to benefits. Those that don't will be subject to immigration enforcement as part of our mass deportation programme - Operation Restoring Justice.
We will also increase the qualifying period to become a UK citizen to seven years. A British passport is a privilege, and will no longer be given away cheaply.
We will introduce an Acute Skills Shortage Visa (ASSV), to be issued in extremely limited numbers, and only when there is clear evidence of acute shortages in national-critical roles. Each ASSV will carry a one-for-one training guarantee: for every visa issued, the sponsoring employer must fund, via a levy, a commensurate training programme to produce a UK worker for that occupation, ensuring that temporary reliance on overseas labour directly builds long-term domestic capacity.
We are putting business on notice: the era of cheap foreign labour is over. We will end bogus sponsors and the ridiculously low salary thresholds. There are millions of Brits currently not in work, it's time we got them to work and stopped our young people from having to compete with infinite migrants.
The result of these changes by a Reform government will be savings to the UK taxpayer well in excess of £230bn. UK welfare will be accessible only to UK citizens. British workers will enjoy priority access to the UK job market. Our borders will be secure. We will once again be a sovereign nation. That's what Prime Minister Nigel Farage will deliver. He will stop the Boriswave. He will put British people first. He will unleash the full potential of our great nation.