The number of sex workers in the Irish Republic has increased by 80% since the Northern Ireland ban was introduced last year, a former prostitute has said.
Around 45 criminal gangs are running prostitution rackets across the Republic and into Northern Ireland, Mia de Faoite claimed.
Paying for sex was outlawed in Northern Ireland in June. Ms de Faoite gave evidence to a group of MPs at Westminster recently.
She said: “When Northern Ireland changed its law, of course they moved south and the women for sale, they increased on our side of the border. It was up by 80%.
“So they moved to where it is legal to buy.”
She testified before the Home Affairs Committee which is investigating prostitution in the UK.
“In the Republic, most prostitution is run by criminal gangs.
“The guards testified at our own Justice Committee that they estimate 45 criminal gangs are now running prostitution rackets across the Republic and into Northern Ireland.”
Northern Ireland became the first part of the UK to make paying for sex a crime when the legislation came into effect last year.
Anyone caught breaking the law could be jailed for up to a year and face a £1,000 fine.
Previously, paid-for consensual sex was legal although activities such as kerb crawling, brothel keeping and pimping were not.
The change was welcomed by Christian organisations but prostitutes’ campaigners argued that it has endangered sex workers by pushing the industry underground.
Sex worker Laura Lee, who is leading a court challenge bidding to overturn the ban, told the committee the prohibition had created problems.
“The difficulty that we have now, for example in Northern Ireland, after the criminalisation went through on 1 June, is that clients are refusing to use the online screening process that we have and so it is putting us into greater danger.
“It is a very, very useful tool to have but in a further criminalised state it can be sadly abandoned, I am afraid.”
Northern Ireland followed Sweden and Norway which have already passed legislation criminalising men who pay for sex.