Teaching leaders and the government have condemned a new website that offers to list schools' workers who have been cleared by the criminal records bureau (CRB).

Peaceofminduk.net, which launches later this month, will charge teachers £12 to be listed on the website, after their CRB record has been authenticated. Organisers say the site will offer parents the chance to see if their child's teacher has been properly vetted.

By law, all teachers are required to be vetted by the CRB before being allowed to teach.

The National Association of Schoolmasters Union of Women Teachers declined to endorse the website when it was approached by organisers, and has warned it may do more harm than good.

NASUWT general secretary Eamonn O'Kane said the site could "prey on the fears of parents" and cause resentment among teachers.

"It is also potentially divisive. Teachers may feel under pressure to pay the £12 fee to sign up if their colleagues have done so. They could also feel vulnerable to allegations from parents if they do not."

He believes the developers are hoping to make money out of "fear and insecurity". The NASUWT is urging members not to register and has warned the education secretary, Charles Clarke, of the site's existence.

John Dunford, general secretary of the Secondary Heads Association, added: "We would not encourage people to use this service. It purports to give a reassurance to parents, which schools are already giving implicitly when they employ people who have been checked. Parents' confidence is more likely to be undermined by the absence of a teacher, who has not paid their fee to this company than by any reassurance about teachers who have paid it."

A spokesman for the Department for Education and Skills advised teachers not to get involved with the site, saying it was not a registered body, and what it proposes to do "does not appear to comply with the CRB's arrangements for information sharing".

But Marie Gildea, the principal developer of the website, said she was "very surprised and very disappointed" with the NASUWT's reaction.

She accused the union of "bullying us with a boycott" and criticised headteachers for letting teachers into schools without the necessary checks.

"My daughter went to junior school and to secondary school and I have no idea who is teaching her on a daily basis. We can trust the schools to a certain extent, but people still slip through the loophole. All we're doing is re-stressing what's already done. Why would a teacher not want to be on here if they have had their CRB check," she said.

She said it was her aim to get every teacher in the country signed up. Until then the site will not make any profit.

Organisers say they plan to donate 10% of all sign up fees to the charity Childline, although the charity has yet to confirm it will accept the money.

The site is due to launch on November 21.