The Liberal Democrats are to hold a special conference to discuss the election of Chris Rennard to the party’s ruling body.

Lord Rennard, who was accused of sexual harassment by four women, was voted on to the federal executive by fellow Lib Dem peers on Thursday, provoking complaints from party members. Rennard has denied any wrongdoing with regards to the harassment claims.

More than 200 members signed a petition that called for a special conference to debate amending the party’s constitution to remove the representation of the Lords on its executive. The party is officially opposed to having an unelected second chamber but has 112 peers compared with eight MPs.

According to the Lib Dem constitution, a special conference is triggered when 200 ordinary members from at least 20 different local parties request it. The petition was signed by enough discontented members from more than 120 local parties within 24 hours.

Once the party’s conference organising committee has verified that all the signatures are from the party’s membership, it has to set a date for the conference within seven days to be held between 21 and 28 days after the notice.

The party’s last special conference was called to approve the coalition agreement with the Conservatives after the 2010 general election.

Grace Goodlad, a member of the Lib Dems’ Rock the Boat group against sexual harassment, which organised the petition, said “too many good people” had left the party as a result of the failure of Rennard and his supporters to accept that “his input is no longer wanted”.

Goodlad said: “The wider membership is appalled at the lack of judgment shown by some of our peers in this election. As a party, it goes against the grain for us to oppose a democratic decision, but it is hard in this case to respect the thoughtless and foolhardy choice made by a group that are not themselves democratically accountable.”

Kat Bavage, a Lib Dem activist who helped run the Rock the Boat campaign, resigned from the party live on Channel 4 News on Thursday evening. Separately, the party’s president, Sal Brinton, who is a peer, wrote to members of the Lib Dem federal executive expressing her disappointment that Rennard had put himself forward and stating that she did not vote for him.

In January 2014, a QC-led investigation said there was insufficient evidence to justify disciplinary action against Rennard, after four activists publicly accused him of touching them inappropriately. Two of the women involved – Bridget Harris, a former adviser to Nick Clegg, and Susan Gaszczak, a former councillor – resigned from the party when Rennard’s suspension was lifted the following August.

The peer, as former chief executive of the party, has apologised if he inadvertently made the “women feel uncomfortable”, but he has always denied sexually inappropriate behaviour.