A newspaper group is to stop running some classified adverts for massage parlours after pressure was put on the company by a Welsh Assembly Member.
Certain adverts have been withdrawn by the newspaper group
Torfaen AM Lynne Neagle accused Media Wales of "hypocrisy" after it carried adverts from massage parlours named as part of alleged sex trafficking.
Ms Neagle said research by her staff appeared to show sex was for sale via some adverts in the group's newspapers.
The group's parent company has now said "particular adverts" were withdrawn.
In a statement, Trinity Mirror, whose newspapers include the Western Mail, South Wales Echo and Wales on Sunday, said: "When this issue was first brought to our attention we initiated a dialogue with South Wales Police.
"In the light of the information that's been provided to us in the last few days, these particular adverts have been withdrawn.
"If we reasonably suspect or become aware of any illegal conduct on the part of a potential advertiser it goes without saying that the advertising will be refused."
Lynne Neagle AM accused Media Wales of hypocrisy
In October, the group was criticised by Ms Neagle for running adverts advertising massage parlours.
Her criticism followed an article in the South Wales Echo which quoted an Amnesty International report that claimed up to 60 women who had been trafficked into the UK were working in Cardiff brothels.
It cited the case of an 18-year-old Lithuanian girl who said she was repeatedly gang raped, beaten and threatened and made to work at three massage parlours in the city.
A leader article in the same edition of the evening paper said the "hideous trade" in sex slavery "must be stopped" and called on "every right-minded citizen" to help police "arrest these vile human traders".
Also in that edition, the newspaper's classified advertising section carried a series of adverts under a column headed "Adult massage".
At the time, Ms Neagle told AMs that all three parlours the paper had referred to had adverts in that column.
She said: "This advertising, carried through papers with whom we advertise, rakes in roughly half a million pounds a year for Media Group Wales.
"That makes them, at least in my eyes, the richest pimps in south Wales," she told AMs.
Alistair Milburn, managing director of Effective Communication and a former editor of the South Wales Echo, said newspaper editors did not have the power to withdraw such adverts.
He told BBC Radio Wales: "As an editor I had to look after, protect the brand of paper, and in my view it was a community newspaper and I would question just where these adverts sat."
Mr Milburn added that there was a danger that the "messenger was being shot".
"These institutions do exist, and I hope now that actually this doesn't get driven totally underground, which could be extremely dangerous."
Ms Neagle wanted the assembly government to withdraw its advertising through the newspaper group. Carwyn Jones, the leader of the house, said he would look into it.