Female employees of the British parliament have created a secret list of members of parliament and other male staff who they say have carried out sexual harassment, British daily The Sun reported on Friday.

Researchers, secretaries and aides set up a group chat on the messaging platform WhatsApp in which they shared names of the men along with details of alleged harassment.

One minister was branded "not safe in taxis." Another post warned of a man that was "very handsy," while another warned to avoid getting the lift with a certain man.

The men named are said to include cabinet ministers, The Sun reported.

"The reports are very concerning, but I can't pre-empt allegations or investigations that haven't come to light yet," May's spokeswoman said when asked about the Sun story.

"The prime minister was very clear when we responded to the reports about Harvey Weinstein in the last few weeks that any unwanted sexual behaviour is completely unacceptable, and that is true in any walk of life including politics."

Separately, a group of women members of Britain's opposition Labour Party have set up a website calling on fellow members who have experienced sexual harassment within party ranks to tell their stories anonymously to try and improve Labour's culture.

"Any allegations that may come to light would be taken extremely seriously and we would advise people to contact the police if there is such an allegation," May's spokeswoman said.

The news surfaced amid a flood of allegations against other powerful men, including Hollywood mogul Harvey Weinstein.