Singapore said on Friday it would ban popular infidelity website AshleyMadison.com from operating in the tightly controlled city-state following concerns over the spread of adultery.

The curbs on the site, which has 22 million members in about 30 countries, illustrate a struggle in Singapore over how far to relax censorship laws.

It now bans Playboy magazine, clips racy scenes from movies and blocks dozens of websites in moves that have added to its image as Asia's "nanny state".

AshleyMadison.com, founded in Canada in 2001, began a Japanese service in June and a Hong Kong service last month. Its operators have announced plans to launch next year in Singapore, which has a population of 5.4 million.

"I do not welcome such a website in Singapore," Minister for Social and Family Development Chan Chun Sing wrote on his Facebook page.

"Promoting infidelity undermines trust and commitment between a husband and wife, which are core to marriage," he said, adding that many Singaporeans shared his view.

AshleyMadison.com's operators have said the site does not make people cheat but rather provides a platform for those who have already decided to have an affair.

The Southeast Asian city-state once banned women's magazine Cosmopolitan and the television show "Sex and the City", though a censored version of the hit HBO series was eventually allowed.

Responding to media queries, Singapore's Media Development Authority indicated it would prevent Ashley Madison from offering its service in Singapore.

"Under the Broadcasting Act, MDA has the powers to act against Internet content providers which violate community standards and social norms, including issuing take-down notices or site-blocking," a spokeswoman said.