US President Joe Biden on Tuesday ordered a review of asylum processing at the US-Mexico border and the immigration system as he seeks to undo some of former President Donald Trump's hardline policies.

Biden also created a task force to reunite migrant families who were separated at the border by Trump's 2018 'zero tolerance' strategy.

"We are going to work to undo the moral and national shame of the previous administration that literally, not figuratively, ripped children from the arms of their families," Biden said, as he signed the three immigration-related executive orders at the White House.

The executive orders called for a dizzying array of reviews and reports that could trigger policy changes in the weeks and months ahead, but provide limited immediate relief to immigrants barred by Trump-era rules.

Immigration advocates have urged the new Democratic administration to quickly undo Trump's policies but Biden aides say they need time to unravel the many layers of immigration restrictions and to put in place more migrant-friendly systems.

"It's not going to happen overnight," White House Press Secretary Jen Psaki said on Tuesday.

The cautious strategy reflects the tightrope Biden is walking to reverse hardline Trump policies while simultaneously trying to prevent a surge in illegal immigration. Biden opponents could also derail or slow down his agenda with lawsuits if his administration moves too quickly and fails to follow proper procedures.

Meanwhile, US Senate on Tuesday confirmed Alejandro Mayorkas to head the Department of Homeland Security, making him the first Latino and immigrant to hold the position and further solidifying President Joe Biden's Cabinet.