LONDON, Nov 19 (Reuters) - Men using prostitutes face prosecution under plans to curb human trafficking, Home Secretary Jacqui Smith said on Wednesday.

The proposals would make it illegal to pay for sex with a prostitute who is controlled by a pimp or trafficker.

Paying for consensual sex would remain legal, but a prostitute-support group said the plans could make life more dangerous for the women by scaring away safer clients.

"I hope that men will think twice about the fact that probably the majority of women in prostitution ... are effectively as good as slaves," she said.

"If you are paying for that, you are part of the problem."

She said men faced a fine of up to 1,000 pounds and a criminal record if found guilty.

Ignorance of a prostitute's dependency would not be a defence. Clients would face prosecution even if they paid for sex believing a woman was operating independently, when that was later shown to be incorrect.

"If you can identify that money has been paid to have sex with a woman and that woman is being controlled, has been trafficked or is being prevented from making a free choice about that, then an offence has been committed," she told BBC television.

Smith said there were around 80,000 women working as prostitutes in Britain and that most did so against their will.

But Niki Adams of the English Collective of Prostitutes disputed the government figures.

"Most women are not working for pimps. Most women are not trafficked," she told BBC radio.

"What we do know is that women from all kinds of walks of life, also working as teachers and students, are working in prostitution. And it is consenting sex."

She said the government plans would endanger prostitutes' lives.

"Women are going to end up taking more risk to get the same kind of business in an economic crisis.

"There is nothing in these proposals to address the poverty debt, homelessness and domestic violence which the government itself acknowledges are factors that force women into prostitution."