The travel operator Tui has ended its sponsorship of the UK and Australian versions of Married at First Sight on Channel 4 after contestants on the former made allegations of rape and sexual misconduct.

An edition of the BBC’s Panorama programme this week revealed allegations by two anonymous women that they had been raped by their on-screen husbands on the show. A third woman, Shona Manderson, accused her on-screen husband of sexual misconduct. All three men deny the claims.

Married at First Sight is a reality show where single contestants are matched by experts before “marrying”. The couples meet for the first time on their “wedding day”.

A spokesperson for Tui UK and Ireland said: “Following the broadcast of the Panorama programme and discussion with Channel 4, we have taken the decision to end our sponsorship of Married at First Sight.”

A Channel 4 spokesperson said: “We’d like to thank Tui for being a valued sponsor of the programme. We look forward to discussing future partnerships.”

The broadcaster also said on Thursday that a Married at First Sight spin-off show remained in pre-production. It announced the launch of Second Marriage at First Sight in February, aiming to bring together contestants from the UK and Australian versions of the show for a second chance at love.

“Whilst we’re in pre-production, we’ve not yet begun filming on Second Marriage at First Sight,” the spokesperson said. “Any findings from our review will be incorporated into the production.”

Melanie Dawes, the chief executive of Ofcom, said the allegations raised “really serious concerns” and that the regulator was willing to tighten guidance around reality shows if needed.

Appearing on ITV’s Good Morning Britain on Thursday, Dawes faced questions about the responsibility on Ofcom after the allegations.

She said: “What we always try to avoid is being really specific about ‘you can do this and you can’t do that’, because fundamentally the responsibility is with Channel 4 and its production company, or with ITV or BBC or whoever is producing these shows, to get this right.

“If they have not got right, this is going to be a serious issue. It’s very live, but it does raise really serious concerns. If we need to tighten our guidance then we absolutely will.”

Channel 4’s chief executive, Priya Dogra, has said she is “deeply sorry” for the women’s distress. Speaking at the launch of the channel’s annual report, she said: “I have watched the programme and heard the women’s accounts, which are very troubling. Their distress is clear and for that I am, of course, deeply sorry.”

She added: “Welfare across all our programmes is hugely important to us, and is a primary concern. However, I’m sure you’ll appreciate that Channel 4 cannot investigate the specific allegations against the men – which they have denied – nor can I comment on them in any way.

“We are a broadcaster, not an adjudicator, and allegations of this type are investigated by other bodies, including when complaints are raised by the police. I do believe that a handling of concerns raised at the time was appropriate, but as I took up the role only recently, I wanted this looked at again.”