A defiant Donald Trump has appeared on Fox News to make a string of fresh voter fraud allegations in his first television appearance since losing the November 3 election.

Speaking with the network's Sunday Morning Futures host Maria Bartiromo via telephone, the outgoing US President insisted he would not accept Democratic Party nominee Joe Biden's victory.

Biden clearly won the election, receiving 306 electoral college votes compared with Trump's 232, and also winning the popular vote by more than six million ballots.

But while Biden won more electoral college votes in 2020 than Trump did in 2016 when he claimed he had defeated Hillary Clinton by a "landslide", he has continued to make unproven claims of voter fraud.

He also made the claim - unsupported by evidence - that the FBI and Department of Justice may be involved in a ploy to "rig" the election

There is no evidence of widespread voter fraud in the 2020 election. There is also no evidence of an attempt to rig the election against the president.

He told Bartiromo the election results came down to "big massive dumps".

"This election was over and then they did dumps — they call them dumps — big massive dumps in Michigan and Pennsylvania and all over," Trump said.

"If you take a look at, you just take a look at just about every state that we're talking about, every swing state that we're talking about. And they did these massive dumps of votes. And all of a sudden I went from winning by a lot to losing by a little."

Unsurprisingly, Trump's awkward choice of words caused the hashtag #massivedumps to trend on Twitter in the wake of the interview.

Meanwhile, the 74-year-old told Bartiromo he won't be backing down.

"My mind will not change in six months," Trump said on air on Sunday.

"There was tremendous cheating here."

"If Republicans allow it to happen, you'll never have another Republican elected in the history of this country, at a Senate level or at a presidential level."

He vowed to use "125 per cent of my energy" to fight the results of the election, but claimed it was "hard" to get the matter to the Supreme Court and slammed the judges who have already rejected some of his legal challenges so far.

"We're not allowed to put in our proof. They say you don't have standing," Trump said.

"I would like to file one nice big beautiful lawsuit, talking about this and many other things, with tremendous proof. We have affidavits, we have hundreds and hundreds of affidavits.

"You mean as President of the United States, I don't have standing? What kind of a court system is this?"

Trump singled out Republican Georgia Governor Brian Kemp for criticism, saying he was "ashamed" he had personally endorsed him after Kemp certified Mr Biden's win in the crucial state.

During the interview, Trump also disputed the fact that Biden ended up with more than 80 million votes, the most ever recorded for a presidential nominee.

"Joe Biden did not get 80 million votes," Trump said without proof, claiming the election was "messed up".

Trump went on to tell Bartiromo in the exclusive interview that he has "not seen anything" from the DOJ or the Federal Bureau of Investigation on investigating the 2020 election.

"This is total fraud and how – the FBI and Department of Justice, I don't know, maybe they're involved – but how people are allowed to get away from this with this stuff is unbelievable," Trump said.

"This election was rigged. This election was a total fraud and it continues to be as they hide.

"And the problem we have, we go to judges and people don't want to get involved.

"You would think if you're in the FBI or Department of Justice, this is the biggest thing you could be looking at.

"Where are they? I've not seen anything.

"They just keep moving along and they go on to the next president," he said.