The speaker's name started trending on social media in Nepal, with many demanding an investigation.

The speaker of Nepal's parliament stepped down on Tuesday after a female employee of the parliament secretariat accused him of rape.

Krishna Bahadur Mahara, a senior member of the ruling Nepal Communist Party said he was stepping down to allow an "impartial and independent investigation into the allegations that have come forward in media reports... until the probe is complete."

A former rebel leader during Nepal's decade-long Maoist insurgency, Mahara has previously served as deputy prime minister and has held several ministerial positions.

In a video interview published by local online news portal hamrakura.com, the woman said that an intoxicated Mahara arrived at her rented home on Sunday night and pursuaded her to drink alcohol before assaulting her.

"I had not thought it would come to this. He forced himself (on me)... he left after I said I will call the police," she said in the interview.

The woman also showed apparent bruises on her arms, hands and feet.

Police confirmed receiving a call from the alleged victim on Sunday night.

"We are taking forward our investigation and have collected evidence from her house. But she has not filed a case yet," said Shyam Lal Gyawali, spokesman for the Metropolitan police unit.

The evidence includes a bottle of whiskey and a pair of broken spectacles, allegedly belonging to Mahara.

The speaker's name started trending on social media in Nepal on Tuesday, with many demanding an investigation.

"We will stay watchful. Impartial investigation is must. Position, reach, victim shaming will not be valued," tweeted woman's rights activist Hima Bista.

Activists say more women are speaking up about cases of sexual violence, but also that many still go unreported in deeply patriarchal Nepal.