Donald Trump is facing a serious backlash over lewd comments he made about women, with John McCain joining a string of Republicans openly denouncing their candidate.

The GOP nominee has also faced criticism from his own VP running mate Mike Pence and a number of high-profile names since footage emerged of him suggesting being famous meant you could do "whatever you want" to women.

Losing the support of well-respected Republican senator and 2008 presidential nominee McCain will be a big blow for Trump

McCain said in comments carried by the BBC: ""Donald Trump's behaviour this week, concluding with the disclosure of his demeaning comments about women and his boasts about sexual assaults, make it impossible to continue to offer even conditional support for his candidacy.

"Cindy, with her strong background in human rights and respect for women, fully agrees with me in this."

He said he would be writing in a vote for a different Republican and joined several women in the GOP who denounced the nominee.

"I wanted to be able to support my party's nominee, chosen by the people, because I feel strongly that we need a change in direction for our country," New Hampshire senator Kelly Ayotte told Politico.

"However, I'm a mom and an American first, and I cannot and will not support a candidate for president who brags about degrading and assaulting women."

Ayotte has already caused problems for Trump after she recently backtracked on comments she made stating the billionaire was "absolutely" a role model for children.

Her decision to denounce Trump was backed by former presidential hopeful Carly Fiorina, whose looks were mocked by the GOP candidate during primary season.

Trump had told a reporter from Rolling Stone magazine in 2015: "Look at that face, would anyone vote for that?

"Can you imagine that, the face of our next president?" he added. "I mean, she's a woman and I'm probably not supposed to say bad things, but really folks, come on, are we serious?"

Fiorina has now released a statement about Trump, stating: "Donald Trump does not represent me or my party.

"I understand the responsibility of Republicans to support their nominee. Our nominee has weighty responsibilities as well. Donald Trump has manifestly failed in these responsibilities.

She added: "Today I ask Donald Trump to step aside and for the RNC to replace him with governor Mike Pence."

However, despite a growing number of people within the Republican Party suggesting Trump should be replaced with Pence, the nominee told The Wall Street Journal "there is zero chance I'll quit".

His sentiments are not shared by former governor of California Arnold Schwarzenegger, who said in a statement reported by Variety: "For the first time since I became a citizen in 1983, I will not vote for the Republican candidate for president."

Schwarzenegger added that people had a duty to choose their country over their political party – in a sentiments increasingly shared by the GOP itself, which is rumoured to be looking at ways to replace the controversial nominee.