The U.S. Supreme Court has said it will consider a challenge to one of President Barack Obama's key immigration reform plans, BBC News reports.

The plan would lift the threat of deportation from five million migrants living illegally in the U.S.

A coalition of 26 mostly conservative states, led by Texas, has been successful in lower court challenges.

A decision from the highest U.S. court is expected in the early summer, just as the U.S. election gets into full swing.

"We are confident that the policies will be upheld as lawful," said White House spokeswoman Brandi Hoffine.

President Obama announced the plan, known as Deferred Action for Parents of Americans and Lawful Permanent Residents (DAPA), in November 2014, BBC says.

He justified using his presidential powers, without Congress, by saying it was in response to inaction over the issue of immigration from Congress.