The government announced last week that a R18+ category for video games would be introduced on January 1, bringing Australia into line with the rest of the world. However, the sex and violence standards for the new category are still to be determined by the Australian Classification Board.

At present, games with sex and violence either receive a MA15+ rating or are banned. Many violent and sexualised games, such as Grand Theft Auto, are edited by manufacturers to qualify for a MA15+ rating.

''I expect the new [R18+] classification to be described no differently to MA15+,'' said the managing director of the Australian Christian Lobby, Jim Wallace.

''If [R18+] is described in looser terms, or is less demanding than the existing MA15+ - which is already letting in things that shouldn't have been there - then it's not going to work.

''We already know that some of the games that are sold in Australia are unacceptable and should never have slipped in under the old rating.''

However, Mr Wallace said he expected the games industry - the Interactive Games and Entertainment Association (iGEA) - to push for an R18+ classification that allowed more sex and violence than the present MA15+ rating. ''They are about increasing their market and their profit,'' he said.

Mr Wallace said he wanted a new, stricter MA15+ category to complement the R18+ rating.

The chief executive of the iGEA, Ron Curry, said he disagreed with the idea that the sex and violence standards applying to MA15+ should apply to the new R18+.

''There's no evidence to suggest … that the content that currently sits there [at MA15+] should only be suitable for adults,'' he said.

A spokesman for the Australian Classification Board, Simon Ferguson, said the details of the new R18+ rating were yet to be finalised. ''It is anticipated that the new MA15+ category will be more stringent than the old,'' he said.