Donald Trump has called for he and Hillary Clinton to take a drugs test before the final presidential debate– after appearing to suggest his rival was using performance-enhancing substances.

The Republican presidential candidate told a rally of supporters in Portsmouth, New Hampshire that Mrs Clinton was getting “pumped up” ahead of Wednesday's third and final presidential debate.

He said: “You want to know the truth? She’s getting pumped up. She’s getting pumped up for Wednesday night."

“We’re like athletes...they make athletes take a drug test. I think we should take a drug test prior to the debate. Why don’t we do that? We should take a drug test – because I don’t know what’s going on with her."

Donald Trump hit by new sexual misconduct claims

“But at the beginning of her last debate she was all pumped up and at the end it was like 'uhh take me down' and she could barely reach her car. I think we should take a drug test. I‘m willing to do it.”

“But at the beginning of her last debate she was all pumped up and at the end it was like 'uhh take me down' and she could barely reach her car. I think we should take a drug test. I‘m willing to do it.”

Some people had previously suggested Mr Trump could be a cocaine user after his frequent sniffing during the secondary presidential debate. Howard Dean, the former Governor of Vermont and chair of the Democrat National Committee, tweeted: “Notice Trump sniffing all the time. Coke user?”

The extraordinary allegations come as new research reveals Mrs Clinton is on course to comfortably win the presidency. The latest results from the Reuters/Ipsos States of the Nation survey suggest that, if the election were held this week, the Democrat's odds of winning are higher than 95 per cent.

The collection of polls suggest Mrs Clinton is on course to win 310 electoral college votes compared to Mr Trump’s 176 – well clear of the 270 needed to secure the presidency. She is predicted to receive 46 per cent of the vote, while Mr Trump is currently on 39 per cent.

To win control of the White House, the Republican candidate was likely need to win key battleground states including Florida, Ohio, Nevada, North Carolina and Colorado.

What did Donald Trump say during the second presidential debate? Show all 8 1 /8 What did Donald Trump say during the second presidential debate? What did Donald Trump say during the second presidential debate? On the leaked tape from 2005 where he talks about sexually assaulting women “I'm very embarrassed by it, I hate it, but it's locker room talk. It's one of those things. I will knock the hell out of Isis” Getty What did Donald Trump say during the second presidential debate? On Hillary Clinton “I hate to say it but if I win I'm going to instruct my attorney general to get a special prosecutor to look into your situation. There has never been so many lies, so much deception. You ought to be ashamed of yourself.” Rex What did Donald Trump say during the second presidential debate? On Bill Clinton “What he's done to women, there's never been anybody in the history of politics in this nation that's been so abusive to women.” AP What did Donald Trump say during the second presidential debate? On whether his alleged opposition to Iraq War had been disproven "It’s not debunked. It’s not debunked." Getty What did Donald Trump say during the second presidential debate? On exploiting tax loopholes "I absolutely used it, and so did Warren Buffett, and so did George Soros and so did many people who Hillary is getting money from." Getty What did Donald Trump say during the second presidential debate? On claims he's sexist “I have great respect for women. Nobody has more respect for women than I do.” Reuters What did Donald Trump say during the second presidential debate? On what he respects about Hillary Clinton “I will say this about Hillary - she doesn't quit, she doesn't give up. I tell it like it is. She's a fighter.” Reuters What did Donald Trump say during the second presidential debate? On his controversial immigration policies "It’s called extreme vetting. We’re going to areas like Syria, where they are coming in by the tens of thousands because of Barack Obama and Hillary Clinton wanting to allow a 550 per cent increase [of refugees] over Obama. People are coming into this country. We have no idea who they are, where they are from and what their feelings are about this country." Getty

But data suggests these states are either on a knife-edge or leaning towards Mrs Clinton.

Despite campaigning heavily in Florida, Mr Trump currently trails his Democrat rival by 6 points.

Mrs Clinton is also pulling ahead in North Carolina and Colorado, but Ohio and Nevada remain too close to call ahead of the 8 November election.

It follows a horrendous week for the Trump campaign in which the candidate has repeatedly been accused of sexism and sexual assault.

After a leaked video from 2005 showed Mr Trump talking about groping females, several women have come forward to claim they were assaulted by the businessman.

He has consistently denies the allegations, claiming today that he had never met the women involved and saying those accusing him of sexual assault were “sick” .