The notices will be sent to hundreds of thousands of EU citizens living in the UK, telling them to apply or risk losing their rights to healthcare and employment.
The deadline for new applications is set to elapse on June 30, with the government insisting there are no plans to extend the deadline - despite calls from campaign groups to do so.
Immigration minister Kevin Foster said the government would “not be extending the deadline” of June 30, adding it has been open since 2019, with EU nationals having been given “the time to apply”.
More than 5.6 million applications have been made to date under the scheme.
Mr Foster said: “I want to be clear, we will not be extending the deadline.
“Put simply, extending the deadline is not the solution to reaching those people who have not yet applied, and we would just be in a position further down the line where we would be asked to extend again, creating more uncertainties.”
Mr Foster stressed anyone who applies by next week’s deadline will “have their rights protected until the conclusion of their application by law”.
He added: “Our message very much is for people not to delay, and apply as soon as they can.”
However, Maike Bohn, co-founder of The3million campaign group, told the Standard: “It is simply unfair to the hundreds of thousands of EU citizens to be left without proof of status which they will need so desperately by the end of June when the citizens' rights grace period is ending.
“Some have not even received a certificate of application yet and could face crippling charges for NHS treatments as they will be seen as unlawful residents.”
The 3million had previously written to Mr Foster calling for an extension to the scheme.
While Mr Foster said that the “high number of applications” meant there were cases still being determined, the minister stressed that people who apply by June 30 “will have their existing rights protected pending the outcome of their application”.
The minister continued: “To ensure there is no loss of rights whilst applications are pending a decision, we are issuing a Certificate of Application to those who submit a valid application by June 30 which they will be able to rely on as proof to access their right to work or rent, when verified by the relevant Home Office checking service.
“They will also be able to enter the UK as a resident and continue to receive benefits and healthcare: essentially, nothing will change for them until their application is concluded.”
He also said people would be able to make late applications to the scheme beyond the June 30 cut-off date, provided there were “reasonable grounds” for this.