Theresa May has described herself as "appalled" by allegations of sexual harassment and groping at the Presidents Club Dinner.
The Prime Minister did not criticise Tory minister Nadhim Zahawi for attending but said that she was "not happy" such an event had taken place.
Her comments came after Mr Zahawi, the children and families minister, was given a "dressing down" by the Tory chief whip.
Speaking from Switzerland on Thursday, just hours after the Presidents Club shut down, Mrs May said the content of the Financial Times report showed that there was a "long way to go" until woman are accepted as equals.
"When I read the report of that event that took place, frankly I was appalled," she said.
"I thought that that sort of approach to women - that objectification of women - was something that we were leaving behind.
"We've made progress but it's very clear that there's a lot more for us to do."
On Wednesday Mr Zahawi told ITV News he had left last week's event early.
The three-decade old club announced its closure soon after allegations surfaced that the male-only guests groped and harassed skimpily-clad hostesses.
Mr Zahawi said he found the dinner, which was hosted by comedian David Walliams, "extremely uncomfortable".
But he was called to see the Tory chief whip late on Thursday where he was rebuked.
Revelations from the event have also led to the resignation of businessman David Meller - a Presidents Club trustee - from his position at Department for Education.
Mrs May is now targeting gagging orders which prevent women reporting from sexual harassment, according to The Times.
A number of beneficiaries of the club, including children's hospital Great Ormond Street Hospital, have said they will refund previous donations.
Evelina London Children's Hospital announced it would be taking a similar measure.
During the fall-out from the allegations, Mr Zahawi tweeted: "I do unequivocally condemn this behaviour.
"The report is truly shocking. I will never attend a men only function ever."
In a later tweet he said he had been "consistent" over his account of events.
"I told No10 and friends that I arrived at 8pm and left at 9:35pm as I felt uncomfortable," he said.
"I did not see any of the horrific events reported by the FT. I am shocked by them and condemn them unequivocally."
One woman who waitressed at the event told ITV News: "We were play things. We were objects for them to gawp at, touch."
She said that the agency workers were treated like "sex workers" who were told to "party and get as drunk as we could".
The Charity Commission has said it is looking into the allegations "as a matter of urgency".
The Presidents Club, which described itself as "appalled" by the allegations, has announced it will distribute remaining funds to children's charities before shutting down in the wake of the scandal.