WASHINGTON President Joe Biden announced one of the biggest legalisation efforts in recent history on Tuesday offering a path to citizenship to hundreds of thousands of immigrants in the US illegally who are married to US citizens. The election year move contrasts sharply with his Republican rival Donald Trump's plan for mass deportations.

The programme will be open to an estimated 500,000 spouses who have lived in the US for at least 10 years as of June 17, the White House and US Department of Homeland Security said in statements on Tuesday. Some 50,000 children under age 21 with a US-citizen parent also will be eligible.

"These actions will promote family unity and strengthen our economy," the White House said in a statement.

Biden, a Democrat seeking a second term in November's presidential election, took office vowing to reverse many restrictive immigration policies of his predecessor Trump, who is also looking to return to the White House. But faced with record levels of migrant arrests at the US-Mexico border, Biden has toughened his approach in recent months.

Earlier this month, Biden barred most migrants crossing the US-Mexico border from requesting asylum, a policy that mirrored a similar Trump-era asylum ban and drew criticism from immigration advocates and some Democrats.

Biden's planned legalisation programme for spouses of US citizens could reinforce his campaign message that he supports a more humane immigration system and show how he differs from Trump, who has long had a hardline stance on both legal and illegal immigration.

The programme will allow the spouses and children to apply for permanent residence without leaving the US, removing a potentially lengthy process and family separation. If they are granted green cards, they could eventually apply for US citizenship.

People who are considered public security threats or who have disqualifying criminal history would not be eligible.

The implementation will roll out in coming months and the majority of likely beneficiaries would be Mexicans, senior Biden administration officials said on a call with reporters.

Biden will speak about the announcement at an event at the White House on Tuesday tied to the anniversary of the Deferred Action for Childhood Arrivals (DACA) programme where he will be accompanied by Democratic lawmakers, immigration advocates, DACA recipients and spouses of undocumented people.

Former president Barack Obama and then-Vice President Biden launched the DACA programme in 2012, another major legalisation effort that currently grants deportation relief and work permits to 528,000 people brought to the US as children.

The Biden administration also announced on Tuesday guidance to make it easier for DACA recipients to obtain skilled-work visas.

US Representative Adriano Espaillat, a Democrat attending Tuesday's event, said the relief for spouses is a way for the administration to balance recent border enforcement measures.

Trump campaign spokesperson Karoline Leavitt called Biden's new programme "amnesty" and in a statement reiterated Trump's deportation pledge, saying he would "restore the rule of law" if reelected.

A little more than half of US voters back deporting all or most immigrants in the US illegally, Reuters/Ipsos polling shows.

At the same time, separate polling by the advocacy group Immigration Hub found 71% of voters in seven election battleground states backed allowing spouses in the US for more than five years to remain.

Rebecca Shi, executive director of the American Business Immigration Coalition, said focus groups conducted by her organisation with independent and Republican voters found they supported legal status for spouses.

"It boosts turnout in terms of Latino and base voters, but it also has support with the middle and the right," she said on a call with reporters on Monday, adding that most people thought the spouses could already legalise.

One couple who could potentially benefit from the action was eagerly awaiting more details.

Megan, a social worker from the election battleground state of Wisconsin, met her husband, Juan, two decades ago when she worked with his cousin and uncle at a restaurant during her college summer break.

Juan's family, from the Mexican state of Michoacan, had come to the US for generations as seasonal workers, with his grandfather participating in a US programme for farmworkers. Juan was in the country illegally, but she never thought it would be an issue.

"I assumed maybe you pay a fine or something," she said. "The punishment is just totally disproportionate."

They have two daughters now - ages four and seven - and still have not found a way to fix Juan's status. Reuters is withholding their last names because of Megan's concern they could face backlash.

Wisconsin does not issue driver's licenves to immigrants in the US illegally, and the couple worry that Juan, who works as a landscaper, could one day be pulled over and deported.

She said the family likely would uproot and relocate to Mexico if Juan was ever sent back.

"It's just a low-level stress that's always there," she said.

  - Reuters