Celebrity Big Brother has sparked more than 11,000 complaints to media regulator Ofcom following allegations of an altercation between two former soap actors taking part in the show.

Former Coronation Street actor Ryan Thomas was given a formal warning on Thursday night’s episode after ex-Emmerdale star Roxanne Pallett complained about his behaviour.

“We are assessing these complaints against our broadcasting rules, before deciding whether or not to investigate,” said Ofcom.

In Thursday’s episode Pallett said she was upset by the altercation, which allegedly took place in the kitchen of the Big Brother house. She said it involved Thomas punching her “repeatedly”, adding: “He actually punched me like a boxer would punch a bag. And we weren’t play-fighting, there was no banter; it wasn’t a joke.”

The show’s producers told her the footage was being reviewed and the matter was being “taken very seriously”. Pallett then asked to sleep in a separate bedroom because she “didn’t feel comfortable” sleeping in the same room.

Roxanne Pallett appearing on Celebrity Big Brother. Photograph: REX/Shutterstock

Thomas insists there was no malice in his behaviour but was called to the show’s diary room, where he was given a formal warning for his behaviour.

“At 3.55pm today Big Brother noticed that, whilst almost play-fighting, you punched Roxanne in the ribs,” the programme said. “This caused Roxanne to say ‘ow, that bloody hurt’. Whether you intended to hurt Roxanne or not is irrelevant.”

Thomas was told: “Before you entered the Big Brother house, rules regarding unacceptable behaviour were explained to you. You have broken this rule.

“Big Brother is issuing you with a formal warning in regards to physical contact in the house. Any repetition and Big Brother may have no choice but to remove you from the house.”

Thomas apologised but insisted he had not intended to hurt her and had been play-fighting: “I think we both know, and Roxanne, that there was no malice or anger in anything I did.”

Channel 5 said it would not be commenting on the incident.

This series of the Channel 5 programme has been hit with controversy after its biggest star Stormy Daniels, the adult film star who claims to have had an affair with US president Donald Trump, pulled out of the show at the last minute.

Another contestant, the “human Ken doll” Rodrigo Alves, was later evicted following a warning for using racist language, while Channel 5 controller Ben Frow has hinted that he is preparing to cancel the series altogether. The broadcaster’s contract to air the show is due to expire at the end of this year.