The latest polls show US Presidential candidate Donald Trump has gained ground on Hillary Clinton this week, despite controversy surrounding his sexual conduct.

Ten women have now come forward to accuse the Republican nominee of unwanted sexual advances.

Trump also caused a furore on Wednesday by claiming the election process is rigged against him and suggesting he may not accept the outcome of the vote.

The latest Reuters/Ipsos poll suggests the election rigging argument has resonated with Trump's voter base.

Democratic candidate Hillary Clinton has seen her lead nearly cut in half - despite 63% of those surveyed admitting they believe Trump has committed sexual assault in the past.

The poll shows Clinton leading Trump by 44% to 40% - meaning her lead has dropped by four percentage points this week.

Prior to this week, the seven-day tracking poll had shown a steady rise in support for Clinton since the end of August - when the candidates were close to tied.

This week's results mean the race is now closer than it has been at any time since a video emerged of Trump bragging about groping and kissing women.

The poll found that 63% of American adults – 34% of whom said they are likely to vote for Trump – agreed with the statement "I believe Donald Trump has committed sexual assault in the past."

The New York real estate mogul has denied all the recent accusations, calling them "totally and absolutely false."

The poll has a “credibility interval” of 3% - meaning results could vary by that much either way.

A US opinion poll average run by The New York Times puts Clinton's lead at 6.1%.