Shabana Mahmood has been called to immediately enact rules to double the time migrants have to wait to apply for permanent settlement in Britain, with data indicating hundreds of thousands will qualify as of next year.
The Government has out plans which will require migrants to wait 10 years before they can apply for the right to remain in the UK indefinitely.
Under current rules, migrants can apply for the right to remain indefinitely after five years.
However, ministers have not yet decided whether it will apply to foreign nationals already in the UK.
Shorter periods of qualification apply to migrants who can prove they have contributed to "economy and society".
Former Home Secretary Yvette Cooper, who Ms Mahmood replaced last week, said a consultation would be put out later this year before a final decision was made.
Home Office figures analysed by The Times have seen renewed calls to apply the changes before hundreds of thousands of migrants who had arrived in the UK since 2021 would be able to qualify for permanent residence.
About 270,000 migrants will become eligible for permanent residency in the UK from next year - known as indefinite leave to remain.
New Home Secretary Shabana Mahmood has been urged to change rules for migrants living in the UK
| PABy 2027, about 416,000 people are set to qualify and a further 628,000 in 2028.
That does not include the people who are already eligible but have not made an application.
Last year saw a 13-year high with 172,798 people granted indefinite leave to remain.
However, those people had moved to the UK before the post-Brexit immigration system, which was established in January 2020 and ultimately led to a rise in arrivals.
Kemi Badenoch conceded her party got the migration system wrong under Boris Johnson
| PAThe rise has been called the "Boriswave" as Boris Johnson was Prime Minister when the new immigration system was implemented.
Due to a pause in immigration due to the Covid pandemic, net migration rose to record levels in the following two years.
Foreigners on study visas or temporary work visas do qualify for indefinite leave to remain, but most work, family and refugee visas do count towards the five-year period.
Up to 1.7 million further people will qualify for permanent residency unless Ms Mahmood doubles the qualifying time to 10 years.
University of Oxford's Migration Observatory Director Madeleine Sumption said: "The number of people with temporary visas in the UK is the highest on record due to unusually high numbers of visas granted in the first three years of the post-Brexit immigration system".
"Even though many will go home and never apply for indefinite leave to remain, we also expect a large increase in the number of people seeking to settle over the next few years," she said.
"This is both because higher immigration naturally leads to higher grants of settlement a few years later, and because higher shares of migrants on study and work visas have been extending their stays in the UK."
Conservative Party Leader Kemi Badenoch conceded her party "got it wrong" under Mr Johnson, with Shadow Home Secretary telling Ms Mahmood to enact the new rules.
He claimed that without doing so, it would put stress on public services and housing.