The culture secretary, Tessa Jowell, has taken the unusual step of condemning an ad campaign that encourages under-18s to gamble online as "utterly reprehensible" and referring it to the Metropolitan police.

ThePool.com, the online betting company behind the campaign, has been ordered personally by the Advertising Standards Authority chairman, Lord Borrie QC, to withdraw the ads while an investigation is conducted.

"I very much welcome this swift and decisive action by the ASA. ThePool.com's campaign is utterly reprehensible. It blatantly uses sex and financial inducements to target under-18s, and uses exploitative and degrading images of women," said Ms Jowell.

"I am also concerned that the type of gambling they are offering may be illegal for under-18-year-olds, and I have asked the Metropolitan police service to look into this.

"Through the Gambling Act 2005 the government is introducing a tough new regime for gambling advertising which will protect young people and promote social responsibility. Campaigns such as this fly in the face of that, and it is right that they are dealt with firmly now and in the future."

The ad campaign, which has appeared in London freesheet Metro, a men's lifestyle magazine and as a promotional leaflet, features scantily clad women and lines such as "Why wait 'til 18? Bet at 16" and "Make lots of money when your friends join too".

Pool gambling is legal for anyone over 16, but all print advertisements appearing in paid-for space must comply with its non-broadcast advertising code.

The ASA will also investigate whether the ads breach the code clauses stating that advertising of gaming services should not encourage excessive gambling, exploit the young or immature or be prepared in a socially irresponsible manner.

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