CHILDREN will be banned from playing the world's most popular computer games, including Grand Theft Auto and Call Of Duty, after the Gillard Government approved classifying them R18+.

The federal Cabinet has approved an adult rating for computer games after finding that many classified as suitable for 15-year-olds in Australia had been ruled suitable for adults only overseas.

As many as 50 games are now available to children as young as 15 but should rightly be played by over-18s only.

Some of the world's top-selling titles, including Grand Theft Auto and Call Of Duty, will fall under the new rating.

Home Affairs Minister Brendan O'Connor will take the Government's new position to a meeting of state and territory attorneys-general this week to seek their approval in changing the games classification system.

"Children and teenagers shouldn't be exposed to the gratuitous sex, violence and adult themes that are contained in some computer games," Mr O'Connor said.

"Over time, we've allowed games to get into the hands of 15-year-olds that would not have been available in comparable countries; that should not have happened." And Mr O'Connor also gave a guarantee he would not allow games that had been banned in Australia to be approved for release under the new R18+ classification, if it is approved.

A change to Australia's classification system requires the agreement of the states and territories as well as the federal government. Many controversial games have been approved for sale to over-15s after being modified slightly to avoid being banned.

One game, Left 4 Dead 2, is a first-person shoot-em-up, as they are known in the gaming world, that was initially banned, then changed to MA 15+ with a warning of "strong bloody violence". Following the reclassification, the Classification Board received 17 complaints that the game was no different to the original.

Other games classified MA 15+ that attracted a large number of complaints included Call of Duty: Modern Warfare 2 and F.E.A.R. 2: Project Origin.

Mr O'Connor said it was relatively simple for gamers to find ways of restoring the games to their original versions using special codes easily available on the internet.

If the Government gets the agreement of the states and territories, it would need to embark on consultations with the gaming industry, gaming advocates, the Christian lobby and various children's groups to sort out how the new classification level would work in practical terms.

Mr O'Connor said he was not sure why it had taken so long for the Government to act on concerns that Australia did not have R18+ rated games.

He said the increasing convergence of films and games, including violent movie adaptations of games such as Resident Evil, had forced their hand to have comparable classification systems.