Retired Vice Admiral Robert Harward has turned down an offer to be US President Donald Trump's new national security adviser.

He said that the Trump administration was "very accommodating to my needs, both professionally and personally" but ultimately said he wanted to enjoy his retirement following 40 years of service in the Navy.

"I'm in a unique position finally after being in the military for 40 years to enjoy some personal time," he said.

Admiral Harward, a former Navy SEAL, was asked whether he had requested to bring in his own staff at the National Security Council (NSC) and replied "I think that's for the president to address".

It was earlier reported that two sources familiar with the decision had said Admiral Harward turned down the job in part because he wanted to bring in his own team.

Admiral Harward served as deputy commander of US Central Command under General James Mattis, who is now defence secretary.

The former national security adviser Michael Flynn tendered his resignation at Trump's request after it emerged he mislead Vice President Mike Pence about his interactions with the US's Russian ambassador, Sergei Kislyak.

"The thing is, he didn't tell our Vice-President properly, and then he said he didn't remember," Mr Trump said at a press conference yesterday. 

"So either way, it wasn't very satisfactory to me."