Immigration enforcement officials will begin giving EU citizens who live in the UK a 28-day warning to apply to remain, the government says.But the Home Office will allow people indefinite time to complete an application for settled status if they have a reasonable excuse for delay.
There is a week to go until the deadline for applications.
Some 5.6 million European Economic Area (EEA) citizens and their dependents have applied for settled status.
But there are around 400,000 cases outstanding, and the government's helpline is receiving thousands of calls a day.
It allows them to retain the same rights of residence, travel, employment and access to healthcare and benefits.
The countries whose nationals have made the highest numbers of applications are Poland (975,000) and Romania (918,000).(BBC)