More Republicans now believe that Democrat Hillary Clinton will win the November presidential election ahead of their own candidate Donald Trump, according to a new survey.

41 per cent of Republicans now expect Mrs Clinton to win the race, versus 40 per cent who say they are still backing Mr Trump, in a Reuters/Ipsos poll released on Wednesday and conducted between October 20 and 24.

Among Mr Trump's supporters, 49 per cent said they believed Trump would win in the latest poll, down from 67 per cent at the beginning of October.

Though within the margin of error, the findings reflected a notable slump in Republican confidence, following a month in which their campaign has had to deal with the fallout of the Trump Tapes and allegations of sexual harassment against their candidate.

Mr Trump also rattled traditional conservatives by claiming the electoral system was rigged and hinting that he would not accept the outcome of the vote if it went against him.

In September, 58 per cent of Republicans said they thought their party's nominee would win, versus 23 per cent who expected Clinton to prevail.

However, despite the abiding pessimism surrounding Mr Trump’s chances and public rebukes made against him by a number of high-profile Republican stalwarts, he still enjoys unwavering support from a commited right-wing fanbase.

In pictures: US Elections 2016 Show all 15 1 /15 In pictures: US Elections 2016 In pictures: US Elections 2016 Democratic U.S. presidential candidate Bernie Sanders speaks to supporters after rival candidate Hillary Clinton was projected as the winner in the Nevada Democratic caucuses Reuters In pictures: US Elections 2016 Democratic presidential candidate Hillary Clinton takes photos with workers at her campaign office in Des Moines, Iowa AP In pictures: US Elections 2016 Republican presidential candidate Mike Huckabee, second from left, prays before lunch with supporters at Drake Diner in Des Moines, Iowa Reuters In pictures: US Elections 2016 Democratic presidential candidate and former Maryland Governor. Martin O'Malley, speaks during a campaign stop in Waterloo, Iowa AP In pictures: US Elections 2016 Democratic presidential candidate Bernie Sanders speaks, as his wife Jane O’Meara Sanders looks on, at a campaign event at Iowa State University Getty In pictures: US Elections 2016 Republican presidential candidate Marco Rubio speaks at St. Ambrose University in Davenport, Iowa Reuters In pictures: US Elections 2016 Republican presidential candidate Ben Carson speaks at a campaign event at Fireside Pub and Steak House in Manchester, Iowa. Getty In pictures: US Elections 2016 Republican presidential candidate Rick Santorum visiting supporters at a house party in West Des Moines, Iowa Reuters In pictures: US Elections 2016 Republican presidential candidate Donald Trump at a campaign event in Cedar Rapids, Iowa AP In pictures: US Elections 2016 Republican candidate Ted Cruz campaigns at Greene County Community Centre in Jefferson, Iowa AP In pictures: US Elections 2016 Senator Rand Paul speaks during a Caucus rally at his Des Moines headquarters in Iowa Getty In pictures: US Elections 2016 Republican candidate Jeb Bush speaks at a campaign event in Des Moines, Iowa AFP In pictures: US Elections 2016 Former Alaska Governor Sarah Palin introducing the arrival of Donald Trump during a campaign rally in Cedar Rapids, Iowa Reuters In pictures: US Elections 2016 A portrait of Democratic candidate Bernie Sanders at his campaign headquarters in Des Moines, Iowa Getty In pictures: US Elections 2016 Campaign badges on sale ahead of a Trump rally at the Ramada Waterloo Hotel and Convention Centre in Waterloo, Iowa Getty

79 per cent of likely Republican voters said they would vote for him, many with the expectation that he would promote a conservative agenda in Congress and appoint conservative justices to the Supreme Court.

The events of the last month also appeared to have played into the hands of the Democratic Party, who are now strongly anticipating a Clinton presidency.

In the poll, some 83 per cent of Democrats said they thought Mrs Clinton would win, while only eight per cent predicted that Trump would become president.

Among Ms Clinton's supporters, 92 per cent expected her to win, up from 83 per cent a month earlier.

While the media has tended to focus on Donald Trump, Ms Clinton has escaped much of the scrutiny levelled at her rival. However, she has also received heavy criticism for using a personal email server to access classified documents.