The UK should sign up to a European convention tackling the "hideous trade" of human trafficking, the Tories say.
Mr Davis said reducing trafficking was a moral imperative
Shadow home secretary David Davis said not enough was being done to tackle the "modern slave trade" which, he said, was "spiralling out of control".
The convention gives victims the right to stay in the UK for at least 30 days, to encourage them to give evidence against their traffickers.
Minister Liam Byrne said the government backed the convention's aims.
The European Convention Against Human Trafficking covers a range of measures including the one to provide temporary, 30-day residence permits to victims to recover from their ordeal and reflect on whether they will help police prosecute offenders.
There are some fears this aspect of the convention - which has been adopted by 34 countries - may be open to abuse by people making false claims of being trafficking victims in a bid to remain in the country.
But Mr Davis denied this would be a "pull factor" for those seeking residence in the UK.
"They are not going to take up a life of being brutalised in the sex trade in order to get residence here," he said.
"The people who make the decisions in this trade are not the victims, the people who make the decisions are the criminals.
"The way to change that decision for them is to catch them, to prosecute them and to punish them and to make sure we protect their victims at the same time."
The Conservatives said there were an estimated 4,000 victims of trafficking for prostitution in the UK during 2003 at any one time, with only 30 convictions for trafficking offences in 2004 - 2006.
Mr Davis said 85% of women in UK brothels were born abroad - 10 years ago it was 15%.
He said trafficking should be the Serious Organised Crime Agency's "top priority", and added that there should be more international police co-operation to chase down criminals, and victims should be offered a helpline and more safe houses.
A border police force should be set up to look for suspicious signs - like swift return tickets or those bought for cash, and to interview adults and children separately to ensure their stories match up.
Asked whether he thought men who paid for sex with trafficking victims should be charged with rape, Mr Davis said he wanted to concentrate on measures that could be implemented immediately.
But he said he hoped to look at ways to encourage men using prostitutes, who they realised were enslaved, to contact the authorities.
Mr Byrne, who is immigration minister, responded by saying: "The UK fully supports the multiple aims of the convention and participated actively in the negotiations."
He said there were no time limits on signing the convention and Home Secretary John Reid was "at present giving the matter his fullest consideration".
Mr Byrne added: "No-one should be under any illusion - unless we introduce identity management and ID cards, we will not be able to effectively fight human trafficking or for that matter identity fraud, organised crime or illegal immigration."