EPAReform UK has announced it would force all migrants holding permanent settled status in the UK to reapply for visas with tougher rules, if the party wins the next election.
Under the plans, Reform will abolish the right of migrants to apply for Indefinite Leave to Remain (ILR) - a permanent status which give migrants rights and access to benefits.
Reform will also unveil plans to bar anyone other than British citizens from accessing welfare. Taken together the party claims their plans would save £234bn over several decades, though this figure is contested.
A government spokesperson dismissed the plans as a "gimmick", adding they were consulting on restricting migrants' access to welfare.
Under the current system, migrants can apply for indefinite leave to remain after five years, giving the right to live and work in the UK permanently.
It is a key route to gaining British citizenship and allows people to claim benefits.
Reform said it would replace ILR with visas that force migrants to reapply every five years. That includes hundreds of thousands of migrants currently in the UK.
Applicants would also have to meet certain criteria, including a higher salary threshold and standard of English.
The government is currently consulting on plans to double the average wait for migrants to apply for ILR from five years to 10.
The announcement launches Reform's fresh assault on what they brand the "Boriswave" - 3.8 million people who entered the UK after Brexit under looser rules brought in by Boris Johnson's administration.
Speaking at a press conference, Reform UK leader Nigel Farage said the "main reason" for the policy was to "wake everybody up to the Boris wave".
Hundreds of thousands of these migrants, who have come to the UK since 2021, will soon qualify for permanent residence under the ILR scheme.
According to a report published on Monday, Reform said it would replace IRL with an increase in the number of entrepreneur and investor routes for migration "supporting founders, innovators, and those willing to commit significant capital to our economy".
Reform will also introduce a new scheme called Acute Skills Shortage Visas (ASSV) for jobs in crisis. Under the scheme, firms can hire one worker from abroad only if they train one at home.
Reform will also raise the average wait for UK citizenship from six years to seven.
Reform say the policy is designed to bring Britain into line with other countries such as the US and United Arab Emirates (UAE) and save the UK more than £234bn over what it calls the "lifetime of the average migrant".
Labour has noted the figure came from a report by the Centre for Policy Studies, a Thatcher-founded think tank, which later said the cost estimates "should no longer be used" after a challenge by the Office for Budget Responsibility.
But Farage said the "exact figure" was not known due to gaps in publicly available data but argued the £234bn figure "is without doubt too low".
Most benefit claimants by people with ILR are EU nationals, whose settled status is protected under the European Union Withdrawal Agreement. It is unclear how Reform's plan to banning all but UK citizens accessing benefits would avoid breaking that deal.
The government spokesperson added: "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."
Writing in The Telegraph newspaper, Reform's policy chief Zia Yusuf said "We are putting business on notice: the era of cheap foreign labour is over."
Yusuf said the changes would lead to "hundreds of thousands of people having to apply and ultimately losing their settled status in the UK".
"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," he said.
"Those that don't will be subject to immigration enforcement as part of our mass deportation programme."
The Liberal Democrats said Reforms proposals were "not serious".
"Businesses would be thrown into disarray, and the UK would lose billions in economic growth and tax revenues," a Lib Dem spokesman said.
World Bank Data shows the UAE has one of the highest proportions of international migrants globally, with migrants making up about 90% of its total labour force.
Indefinite leave to remain (ILR) is the UK's immigration status that allows non-British citizens the right to live, work and study in the UK.
It is usually possible for someone to apply for ILR if they have worked in the UK for five years, although it can be two or three years if they came to UK on particular visas.
Applicants must usually meet English language requirements, have no serious criminal record and may have to pass the Life in the UK test.
A person can currently apply for British citizenship, 12 months after they have been granted indefinite leave to remain.
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