Police across the UK are going on duty at ports and airports in an operation aiming to help young women who may be victims of human traffickers.
People smugglers force women to work in the illegal sex trade
Officers will hand out leaflets asking women if they really know what they will be doing in the UK and whether anyone has taken their passport.
A helpline is also being opened for those who fear they will be forced to work in brothels and massage parlours.
Police said they wanted to end the "exploitation" of such women.
As part of Operation Pentameter, posters will also be put up to heighten awareness of those being unsuspectingly lured into the country to work in the sex trade.
Chief Constable Tim Brain, of Operation Pentameter, told the BBC there was a need "to raise awareness with the travel industry, the general public and women who are being exploited through traffickers".
The operation was targeting women who were "coming to work in this country as prostitutes and then being coerced and exploited while they are here".
Police chiefs and the government want all 55 forces in the UK to have fully outlined plans for dealing with human trafficking.
Ministers have yet to decide whether to accept a European agreement which gives victims an automatic right to stay in the UK for six months.
Permission to stay
In January, it emerged that ministers were considering offering victims permission to stay in the UK temporarily by offering an automatic "reflection period".
Under the current system, the fate of trafficking victims is decided on the merits of their individual case.
Amnesty International UK Director Kate Allen welcomed the police operation, but said it did not go far enough.
"Currently victims of trafficking have almost no rights in the UK. In the eyes of the law they are simply illegal immigrants and are routinely detained and deported," she said.
"The government should sign the European Convention Against Trafficking - something it could do tomorrow.
"Signing would turn the system around, so that trafficked women are recognised as the victims and not the perpetrators of crime."
Chris Beddoe, director of Child Prostitution and Trafficking of Children for Sexual Exploitation International UK (ECPAT), a campaign group against child prostitution and trafficking, said the operation was "a foot in the right direction".
"Police and other professionals need to be aware that some of these victims may indeed think they are protecting the very people who traffic them, so, there are a lot of issues to be concerned about."
Natalia Dawkins from the Poppy Project, which provides support and accommodation for women who have been trafficked for sexual exploitation, said it had helped 421 women since March 2003.
"They are an invisible, exploited workforce and, disturbingly in too many cases, expendable commodities," she said.
"The women we have helped have reported that their only possessions have been cheap underwear, their surroundings a dingy room and their only company a succession of strange men."