Trump hit by his own lewd remarks about women caught on tape

Trump boasted in vulgar terms about trying to have sex with an unidentified married woman and groping women.

Presumptive US Republican presidential candidate Donald Trump arrives to address a campaign rally at Grant Park Event Center in Westfield, Indiana. Picture: AFP.

NEW YORK - Republican presidential candidate Donald Trump came under fire from his own party on Friday after a bombshell 2005 recording came to light in which he boasted in vulgar terms about trying to have sex with an unidentified married woman and groping women, saying "when you're a star, they let you do it."

A stream of Republican leaders denounced the remarks, first published by the Washington Post, which threaten Trump's already shaky standing with women voters just a month ahead of the 8 November presidential election.

WATCH: Trump apologises for lewd talk caught on tape in 2005.

House of Representatives Speaker Paul Ryan, the top Republican elected official, said he was "sickened" by the comments and said Trump would no longer attend a campaign event in Wisconsin with him on Saturday.

"I hope Mr Trump treats this situation with the seriousness it deserves and works to demonstrate to the country that he has greater respect for women than this clip suggests," Ryan said in a statement.

Reince Preibus, chairman of the Republican National Committee, said: "No woman should ever be described in these terms or talked about in this manner. Ever."

Senate Majority Leader Mitch McConnell said the comments were "repugnant" and that Trump "needs to apologise directly to women and girls everywhere."

Trump said his running mate Mike Pence would travel to Wisconsin in his place and he would spend time with Preibus and other advisers preparing for Sunday's second presidential debate in St. Louis with Democratic candidate Hillary Clinton.

In a statement, Trump shrugged off the leaked tape as "locker room banter, a private conversation that took place many years ago."

In the recorded conversation, Trump was wearing a microphone and chatting on a bus with Billy Bush, then host of NBC's Access Hollywood ahead of a segment they were about to tape.

"I did try and fuck her. She was married," Trump said. "I moved on her like a bitch, but I couldn't get there."

Trump talked about his attraction to beautiful women. "I just start kissing them," he said.

"And when you're a star they let you do it," he said.

"Grab them by the pussy. You can do anything."

Trump, who has brought up former President Bill Clinton's infidelities as a criticism of Hillary Clinton, calling her a "total enabler," responded to the audio.

"Bill Clinton has said far worse to me on the golf course - not even close. I apologise if anyone was offended," Trump said.

Access Hollywood confirmed the video in its own report, saying it discovered the comments in its library.

Billy Bush said in a statement to Variety he was "embarrassed and ashamed" of his comments.

Jeb Bush, the former Florida governor who lost to Trump in the Republican presidential primaries - and who is a cousin to Billy Bush - said on Twitter the comments were "reprehensible."

Republican Senator Mark Kirk, who is in a tough re-election race in Illinois, said Trump should quit the race and called him "a malignant clown" who is "unfit" to be president.

Other prominent Republicans also condemned the comments but stopped short of withdrawing their support for their candidate, including Arizona Senator John McCain and Texas Senator Ted Cruz.