A BBC News investigation last week heard from 13 people spanning a range of ages, who worked across five different programmes, who made allegations of inappropriate sexual comments.
Production company Banijay UK said it has launched an investigation, with which Wallace was co-operating, while the BBC has said it will “always listen if people want to make us aware of something directly”.
People who have come forward with allegations against Wallace include former BBC Newsnight presenter Kirsty Wark, who said he told stories and jokes of a “sexualised nature” in front of contestants and crew when she was on Celebrity MasterChef.
Other allegations we have heard include Wallace talking openly about his sex life, taking his top off in front of a female worker saying he wanted to “give her a fashion show”, and telling a junior female colleague he wasn’t wearing any boxer shorts under his jeans.
On Monday, the BBC came under mounting pressure to consider pausing MasterChef while Wallace is investigated.
Rupa Huq MP, who is a member of the Culture, Media and Sport Committee, said the continued broadcast of MasterChef could be “triggering” for the women involved.
The BBC confirmed later in the day that all MasterChef episodes filmed would be aired as planned, including the Christmas specials.
But on Tuesday, in a change of position, it was revealed that the festive specials will now no longer be aired.
A BBC spokesperson said: “As we have said, MasterChef is an amazing competition which is life-changing for the chefs taking part and the current series of MasterChef: The Professionals is continuing as planned.
“The celebrity Christmas specials are obviously a different type of show and in the current circumstances we have decided not to broadcast them.”
It is understood the celebrity contestants involved in the Christmas special are being spoken to about the reasons behind the decision to pull the show.
The first, a Celebrity MasterChef Christmas Cook Off, featured The Wanted singer Max George, Emmerdale actor Amy Walsh, reality star Luca Bish and comedian Shazia Mirza.
The second, called MasterChef Meets Strictly Festive Extravaganza, was due to feature Strictly Come Dancing’s Amy Dowden, Gorka Marquez, Kai Widdrington and Nancy Xu, with Motsi Mabuse setting a challenge.
Three repeats of an old series of Inside the Factory will no longer be shown on BBC Two in the lead up to Christmas, the BBC spokesperson said.
There will no changes to iPlayer content.