Jeremy Corbyn will accuse Westminster of being home to a culture in which the abuse of women is accepted and normalised, in a speech on Saturday.
The Labour leader will say: "It is a warped and degrading culture that also exists and thrives in the corridors of power, including in Westminster."
He will urge survivors of assault and harassment to report their experiences to authorities, arguing that the "problem doesn't stop with those who make unwanted advances on women" but "extends to a culture that had tolerated abuse for far too long".
Mr Corbyn will also say that MPs who sexually abuse and harass women will be held accountable for their actions.
His remarks come in the wake of reports of extensive sexual harassment around Westminster, including claims that four MPs, one of whom is a minister, have been accused of sexual misconduct.
The Labour leader has been accused of failing to act quickly enough following the revelation of homophobic and misogynistic comments by Labour MP Jared O'Mara.
His address, to Unite union's Scottish Policy Conference, follows comments made to LBC Radio that "there has to be a proper system of people, women in particular, being able to report if they've been abused in any way and have it dealt with in a timely and proper manner.
"Our party, the Labour Party, has a process of doing that both for employees of party officials, MPs and councillors, but also for party members who feel they've been abused in any way," he said.
Downing Street has said any allegations will be taken "extremely seriously" and Theresa May has urged anyone with information about the "deeply concerning" claims of sexual harassment to come forward.
According to The Sun, female employees in Westminster have resorted to using a WhatsApp group to warn members about MPs and other senior figures from across the political parties who are known for sexual harassment.
Theresa May was said to be unaware of allegations having been reported but said "serious action would be taken where it's necessary".
"Any unwanted sexual behaviour is completely unacceptable, and that is true in any walk of life – including politics," a spokeswoman said.
The statements follow a report in The Times which has identified, but not named, two Labour MPs and two Conservative MPs who have been accused of harassment or inappropriate behaviour.
Their violations are said to range from inappropriate texts and unwanted passes to affairs with young researchers.
Equalities Minister Justine Greening also demanded abusive behaviour towards women at Westminster be stamped out.
She told Sky News: "There is no place in Westminster for this kind of behaviour. Women who experience it should be coming forward to be clear about what has happened to them.
"It is now long overdue that we stamp this behaviour out."Let's