Caroline Spelman, who was Environment Secretary from 2010 to 2012, said she supported the so-called ‘Nordic model’ seen in Sweden, Iceland and Norway that makes buying sexual services - but not selling them - a crime.
She also called on male politicians to make their views on the subject clear.
Mrs Spelman told The Guardian: “I think the Nordic law is the right direction, but we need cross-party support for it.
“It’s very important men come out and say what they think as well because it’s very emotive.”
Under current laws, selling sex behind closed doors is legal and buying sex is allowed as long as a prostitute is not exploited by a third party for gain or encouraged into providing sexual services. There are also laws in Scotland, England and Wales against running brothels, soliciting and kerb-crawling.
A bid to make prostitution illegal in Scotland was rejected by MSPs in 2012.
Mrs Spelman said she was shocked by estimates that thousands of prostitutes in the UK had been victims of trafficking and said she believed reducing demand would be necessary to address such sexual exploitation.
She was backed in her support for the Nordic model by another Tory MP, Sarah Wollaston, who criticised the system of full legalisation of prostitution in Germany as leading to “horrific exploitation”, The Guardian said.
Prostitutes against move
The call for Britain to adopt the Nordic model was backed last month by a group of cross-party MPs.
But sex workers hit back, arguing that prostitution would not be stopped by criminalising people who pay for sex, the Guardian said.
Cari Mitchell, of the English Collective of Prostitutes, said: “We are appalled that at a time when benefit cuts and sanctions, increased homelessness and debt are forcing more women, particularly mothers, into prostitution, the best that MPs can come up with is to increase criminalisation.”
Last month the European Parliament passed a non-binding resolution to criminalise the buying of sex, which will lend weight to calls for member states to re-examine their policies.
The Home Office has no plans to review prostitution laws, the newspaper said, and Home Secretary Theresa May opposed calls in 2008 for clients rather than prostitutes to be criminalised.