Hillary Clinton is flatlining in the polls even though voters think she won the second debate - and despite the Republican Party's meltdown following the release of Trump's video.

Clinton captures 42 per cent of the vote to Trump's 37 per cent, according to a Politico/Morning Consult poll conducted the day after the debate, and published Tuesday. Libertarian Gary Johnson gets 10 per cent and the Green Party's Jill Stein gets 3.

Clinton's share is the same as it was in surveys both before and after the release of the video showing Trump making lewd remarks about women.

Clinton has stagnated at 42 per cent, according to the Politico/Morning Consult poll published Tuesday

And in a separate NBC News/Wall Street Journal survey conducted after both the debate and the release of the footage, Trump regained a little ground, the results showed Tuesday.

The Republican gets 37 per cent to Clinton's 46.

The results are an add-on to the news organizations' poll conducted over the weekend, which found an 11-point gap between the two candidates. Trump scraped in at 35 points while Clinton got 46.

The updated version includes responses taken on Monday, after the debate. It apparently shows Trump recovering from the video scandal to make headway following his debate performance.

Still, the Republican party was in turmoil on Tuesday as warring factions were split over whether or not to back the real estate mogul.

The Politico/Morning Consult poll showed that although three-quarters of Republicans think their party is divided, with election day less than a month away 77 per cent want the GOP to keep supporting him.

Experts have already said that, despite calls by some senior Republicans to replace him, removing the candidate at so late a stage would be nigh on impossible. Absentee ballots have already been sent out in a number of states.

The Politico/Morning Consult poll was the first full, official survey to be conducted since the debate, aside from snap surveys and online reaction.

A snap CNN/ORC poll in the hours after the showdown put Clinton as the winner at 57 to 34 per cent - but that survey's respondents were just 27 per cent Republican, against 36 per cent Democrats and 37 per cent independents.

Trump's 37 points in the Politico/Morning Consult results is actually slightly higher than the share he got before both the debate and the emergence of the 2005 footage.

In a September 30-October 2 survey he got 36 points, while immediately after the video's release he was at 38, an October 8 survey found.

The margin of error is plus or minus three percentage points.

The debate saw Clinton trounce Trump, according to the survey, with 42 per cent of respondents saying she won - including 13 per cent of Republicans. Just 28 per cent thought Trump won.

The findings show Clinton is making little headway despite her rival's troubles.

However the poll does paint a picture of a divided Republican party. Three quarters of voters, and the same proportion of Republicans say the GOP is divided. Just one in ten think it is united.

'What has skyrocketed is that three quarters of Republicans now view their party as divided. That is up 20 points since the GOP convention in Cleveland,' said Kyle Dropp, Morning Consult's co-founder and chief research officer.

Since the emergence of the footage Trump has been deserted by dozens of Republican representatives, including former candidate and Arizona senator John McCain, and Illinois senator Mark Kirk.

But the billionaire t old The Washington Post on Saturday that he would not step down.

'I’d never withdraw. I’ve never withdrawn in my life,' he said.

The nation's most powerful Republican, House Speaker Paul Ryan, told colleagues on Monday that 'you all need to do what's best for you and your district'.

He is no longer campaigning with Trump but hasn't withdrawn his endorsement.