The Lib Dems have brought forward their selection process to find a new candidate for Sheffield Hallam in response to the suspension of the sitting Labour MP Jared O'Mara.
The move follows further allegations of sexist and misogynistic comments posted by Mr O'Mara on internet forums prior to his election.
It also follows reports that the Labour Party knew about the claims a month ago despite claiming it only found out about the comments on Monday.
The party has now launched an investigation into the MP amid calls for his resignation.
Mr O'Mara is facing accusations of sexism, homophobia and xenophobia following the publication of comments he appears to have posted to websites in his 20s.
The extracts include examples of highly sexualised language as well as personal attacks on celebrities like Jamie Cullum and Michelle McManus.
The 36-year-old issued an apology to on Monday and again on Tuesday, blaming his past behaviour on a "lad culture" which "warped [his] mindset".
The Labour Party announced an investigation into the allegations on Tuesday, but following pressure from cross-party MPs, it went a step further yesterday and issued a suspension.
The Lib Dems have now confirmed they are pressing forward with their selection process to find a new candidate to contest the seat.
It is understood that there are five candidates, but Mr O'Mara's predecessor, Nick Clegg, is not among them.
There are also several online petitions circulating calling for the MP to resign.