Less than 24-hours before Donald Trump is set to announce his so-called knowledge of Russia hacking, one of his top intelligence advisers has quit his team.

Former CIA director James Woolsey will no longer serve as an adviser to the President-elect or be part of the transition team as he was reportedly "excluded" from talks.

Mr Woolsey’s spokesman, Jonathan Franks, said that his departure will be "effective immediately".

"He wishes the president-elect and his administration great success in their time in office," his statement added.

Mr Woolsey, the former director of national intelligence, was criticised last week for saying that Mr Trump might be "playing us" regarding his apparent knowledge about the alleged involvement of Russia in the presidential election.

"There’s a possibility that he is [playing us] a little bit," he said, following Mr Trump’s comments at his Mar-a-Lago resort that he would talk about the hack on Tuesday or Wednesday of this week.

"I know a lot about hacking," Mr Trump told reporters.

"And hacking is a very hard thing to prove. So it could be somebody else."

Mr Trump tweeted earlier this week that the intelligence briefing on Russia that he was supposed to receive had been delayed until Friday, which he said was “very strange”.

The public questioning was seen as another blow to intelligence agencies who he is expected to entrust to inform him of national security.

Trump's advisor suggests Obama's sanctions against Russia are to 'box in' the incoming President

Mr Woolsey also dismissed the importance of the CIA’s report that concluded Russia was behind the attack.

"We may see as time goes on an improved technology for sorting things out in the hacking world, but it is probably not always a good idea to say in these days and times that we know it was Russia, it was only Russia," he told CNN.

"No, I'd be a little more cautious than that... I think the Russians were in there, but it doesn't mean other people weren't."

Mr Trump said that the hacker could have been a teenager or "a guy sitting on their bed who weighs 400 pounds". His aides have argued that sanctions against Russia, imposed by president Barack Obama, "boxed in" the president-elect, and that more focus should be on "punishing" Hillary Clinton instead.

Mr Woolsey’s departure from the Trump transition team comes almost two months after the resignation of Mike Rogers, the former house intelligence committee chairman.