Too many powerful men working late into the night has led to a culture of sexual harassment in Parliament, according to Labour's deputy leader.
Harriet Harman said there is a problem in Westminster "partly because it is male dominated" and "partly because of the hours and people being away from home".
The shadow culture secretary said Labour was reviewing its codes of conduct to set out what is unacceptable behaviour and how it should be dealt with.
Following a week in which Parliament's reputation plummeted further after sleaze and expenses claims, Ms Harman also called for the MPs' allowances system to be reformed again.
Ms Harman told BBC Radio 4's Today programme: "I do think we need to change the system on expenses ... because it is unfinished businesses in terms of assuring the public that we really have sorted the situation out."
A Channel 4 News investigation earlier this week claimed there was a prevailing "climate of sexual harassment" in Parliament after interviewing 70 people from "all political parties and sexual orientations".
It said young men were more likely to be sexually harassed than women, with 40% of the men interviewed saying they had received unwanted sexual advances.
A third of those interviewed said they had personally experienced sexual harassment, while almost a quarter said they had witnessed someone else being sexually harassed, or that a friend had confided in them about being harassed.
Ms Harman said: "When it comes to sexual harassment we certainly have been looking again at our codes of conduct which we've had for some time in the party, which sets out specifically what behaviour is not acceptable for an employer towards their employee in terms of sexual harassment and what the procedures are to deal with it."
She added: " Certainly when I first arrived if you had very, very long hours, people working beyond 10pm. If you have people away from home and you have a male hierarchy that is a recipe for a culture in which sexual harassment can prevail.
"And therefore you have to have very strong procedures and send down the message that this is not acceptable, that you should be encouraged to complain and your complaint will be dealt with."
The Conservatives are sending a new voluntary code of conduct to MPs setting out "a basic statement of what should be best practice in the workplace".
Tory Douglas Carswell told Today he did not recognise descriptions of Parliament as the "Palace of Sexminster".
He added: "Of course, if you have 650 bosses you are going to get some who aren't very good at managing people."
The Conservative MP said giving voters the ability to sack MPs would "hugely change the culture" in Westminster.
"What we need ultimately is a right for voters to intervene and to sack MPs. That means a right of recall."