(Adds details of lawsuit, background)
WASHINGTON, March 3 (Reuters) - A U.S. appeals court in Washington said on Tuesday it would hear oral arguments on May 4 in a challenge against President Barack Obama's immigration executive actions.
A federal judge in December threw out a lawsuit brought by Joe Arpaio, an Arizona sheriff who called the sweeping changes unconstitutional. Arpaio appealed the ruling to the U.S. Court of Appeals for the District of Columbia Circuit.
Arpaio's lawsuit said the changes amounted to an amnesty and would encourage more people to cross the border illegally.
The Obama administration has been fending off court actions designed to halt immigration actions that would grant relief from deportation for 4.7 million people who are in the United States illegally.
Last week, the U.S. Department of Justice requested an emergency stay to put on hold a Texas judge's decision that temporarily blocked Obama's actions.
The executive orders have also become a flashpoint in Congress where House Republicans unsuccessfully threatened to withhold funding from the Department of Homeland Security if provisions were not included to block Obama's actions. (Reporting by Emily Stephenson, Lindsay Dunsmuir; Editing by Peter Cooney and Ken Wills)