Shabana Mahmood will announce sweeping new rules on Monday on how long legal migrants must wait for settlement in the UK, with most likely to wait a decade and some up to 15 years.

Ministers – including the housing secretary, Angela Rayner – had raised concerns about the effect the rules would have on care workers already in the UK who would be likely to face a 15-year wait for settlement, also known as indefinite leave to remain (ILR).

The government’s response to the consultation on the reforms, which will be put before MPs on Monday, is expected give some exemption to care workers already in the UK, though most other professions will face the lengthy waits for settlement.

Mahmood, the home secretary, has proposed that the settlement wait could be reduced if legal migrants showed they had contributed to their local communities via a “points based system” or if they were earning higher incomes.

She is expected to meet union general secretaries on Monday – some of whom have raised alarm at the changes –…