Anti-human trafficking coordinator starts work in Wales
Wales' first anti-human trafficking coordinator says his first task in the post will be to find how big the problem is.
Robert Tooby' said the cost was £32bn globally, but the extent in Wales was not known.
Mr Tooby, a former police chief, said "Victims are suffering from horrendous assaults on themselves and slavery."
There have been claims the funding for his post could be better spent elsewhere.
But Mr Tooby said it was important to have a "cohesive response" to the problem in Wales.
The assembly government, which is funding his post, said human trafficking was now the third most lucrative market in the UK for organised criminals, after drugs and firearms.
According to police at least 2,600 women are thought to be working as prostitutes in Wales and England, having been trafficked from abroad.
Mr Tooby told BBC Radio Wales:"At the moment we're talking small figures, so you're talking perhaps 30 children and an equivalent amount of adults. But we need to get to the bottom of understanding how many there are.
"You look across from Gwynedd down to Pembroke and indeed in the bigger cities Wrexham, Cardiff, Newport and Swansea, there's certainly evidence to say it is happening."
Part of his role will be to help professionals, including police, councils, health service providers and voluntary organisations, identify and intervene in cases.
A former chief superintendent, who was commander of policing in Cardiff for five years, he will also work with agencies around the UK and abroad.
Last year, the post was criticised by the head of the Terrence Higgins Trust, Pete Clark, who said the money would be better spent helping existing sex workers.
Mr Tooby said: "I think a lot of the charities and indeed the public bodies, the police and health, have been doing a lot of work.
"But they have been doing a lot of work in silos and it's important to get together and have a cohesive response to it across Wales.
"I think it's important to gel us all together.
"It's important to understand the problem across the whole of Wales and to put up barriers, to respond to the victims, firstly, to understand the actual needs of the victims but not to be in denial."