President Joe Biden is taking an expansive, election-year step to offer relief to potentially hundreds of thousands of immigrants without legal status in the US — aiming to balance his own aggressive crackdown on the border earlier this month that enraged advocates and many Democratic lawmakers.

The White House announced on Tuesday that the Biden administration will, in the coming months, allow certain spouses of US citizens without legal status to apply for permanent residency and eventually, citizenship. The move could affect upwards of half a million immigrants, according to senior administration officials.

To qualify, an immigrant must have lived in the United States for 10 years as of Monday and be married to a US citizen. If a qualifying immigrant's application is approved, he or she would have three years to apply for a green card, and receive a temporary work permit and be shielded from deportation in the meantime.

About 50,000 noncitizen children with a parent who is married to a US citizen could also potentially qualify for the same process, according to senior administration officials who briefed reporters on the proposal on condition of anonymity.

There is no requirement on how long the couple must have been married, and no one becomes eligible after Monday.

That means immigrants who reach that 10 year mark any time after June 17, 2024, will not qualify for the programme, according to the officials.

Senior administration officials said they anticipate the process will be open for applications by the end of the summer, and fees to apply have yet to be determined.

Biden will speak about his plans at a Tuesday afternoon event at the White House, which will also mark the 12th anniversary of the Deferred Action for Childhood Arrivals programme, a popular Obama-era directive that offered deportation protections and temporary work permits for young immigrants who lack legal status.

White House officials privately encouraged Democrats in the House, which is in recess this week, to travel back to Washington to attend the announcement.

The president will also announce new regulations that will allow certain DACA beneficiaries and other young immigrants to more easily qualify for long-established work visas. That would allow qualifying immigrants to have protection that is sturdier than the work permits offered by DACA, which is currently facing legal challenges and is no longer taking new applications.

The power that Biden is invoking with his Tuesday announcement for spouses is not a novel one. The policy would expand on authority used by presidents George W. Bush and Barack Obama to allow “parole in place” for family members of military members, said Andrea Flores, a former policy adviser in the Obama and Biden administrations who is now a vice president at FWD.us, an immigration advocacy organisation.

The parole-in-place process allows qualifying immigrants to get on the path to US permanent residency without leaving the country, removing a common barrier for those without legal status but married to Americans. Flores said it “fulfils President Biden's day one promise to protect undocumented immigrants and their American families”.

Tuesday's announcement comes two weeks after Biden unveiled a sweeping crackdown at the US-Mexico border that effectively halted asylum claims for those arriving between officially designated ports of entry. Immigrant-rights groups have sued the Biden administration over that directive, which a senior administration official said on Monday had led to fewer border encounters between ports.