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.