Joe Biden won't rule out 2020 presidential campaign

Joe Biden (AAP)
Joe Biden (AAP)

Outgoing US Vice President Joe Biden has doubled down on comments linking him to a push to become leader of the country in four years' time.

Mr Biden has been openly critical of President-elect Donald Trump since the business mogul announced he would be running back in 2015. Mr Trump's successful campaign left Mr Biden and many other Democrats dissatisfied.

The 74-year-old caused a stir on Monday (local time) after delivering a surprising response to a reporter asking if he would consider a tilt for US President in 2020.

"Yeah, I am. I'm going to run in 2020," Mr Biden replied.

When asked to clarify, Mr Biden responded, "For President. What the hell, man."

However he immediately backed off, saying: "I'm not committing not to run. I'm not committing to anything."

But on Tuesday night (local time) political talk show host Stephen Colbert put the question to him again, quoting him the transcript of that exchange - and Mr Biden once more refused to rule out a presidential push.

"I'm a great respecter of fate," he explained. "I don't plan on running again, but to say you know what's going to happen in four years is not rational."

Colbert then pressed him to comment further, saying "that is the sound of a door creaking open" - but Mr Biden made it clear such a move is unlikely at this stage.

"I can't see the circumstance in which I'd run, but what I learned a long, long time ago is to never say never.

"You don't know what's going to happen. Hell, Donald Trump's going to be 74, I'll be 77 and in better shape - what the heck?" he joked.

Mr Biden has been President Barack Obama's deputy for the eight years he has been in power.