If he wins the presidency, Republican presidential nominee Donald Trump would seek to purge the federal government of officials appointed by Democratic President Barack Obama and could ask congress to pass legislation making it easier to fire public workers, Trump ally Chris Christie says.

Christie, who is governor of New Jersey and leads Trump's White House transition team, said the campaign was drawing up a list of federal government employees to fire if Trump defeats Democratic rival Hillary Clinton in the November 8 presidential election.

"As you know from his other career, Donald likes to fire people," Christie told a closed-door meeting with dozens of donors at the Republican National Convention in Cleveland, according to an audio recording obtained by Reuters and two participants in the meeting.

Christie was referring to Trump's starring role in the long-running television show The Apprentice, where his catch-phrase was "You're fired!"

The Trump campaign did not respond to requests for comment.

Trump's transition advisers fear that Obama may convert these appointees to civil servants, who have more job security than officials who have been politically appointed.

This would allow officials to keep their jobs in a new, possibly Republican, administration, Christie said.

"It's called burrowing," Christie said. "You take them from the political appointee side into the civil service side, in order to try to set up ... roadblocks for your successor, kind of like when all the Clinton people took all the Ws off the keyboard when George Bush was coming into the White House."

Christie was referring to pranks committed during the presidential transition from Bill Clinton to George W. Bush in 2001.

During that period, some White House staffers removed the W key on computer keyboards and left derogatory signs and stickers in offices, according to a report by the General Accounting Office, an investigative arm of congress.

"One of the things I have suggested to Donald is that we have to immediately ask the Republican congress to change the civil service laws. Because if they do, it will make it a lot easier to fire those people," Christie said.

There was no immediate comment from the American Federation of Government Employees, which is the largest federal employee union in the US.

Christie also told the gathering that changing the leadership of the Environmental Protection Agency, long a target of Republicans concerned about over regulation, would be a top priority for Trump should he win in November.

Trump has previously vowed to eliminate the EPA and roll back some of America's most ambitious environmental policies, actions that he says would revive the US oil and coal industries and bolster national security.