New South Wales has pledged its support for an R18+ rating for video games, paving the way for the Federal Government to begin drafting the legislation to introduce the new classification.

The proposal won the in-principle support of most states and territories at a meeting of attorneys-general last month, but NSW attorney-general Greg Smith abstained from the proposal, saying he needed more time to consider the new system.

The state's Cabinet has now given its "in-principle" backing to the adult-only rating.

"Few people would dispute the value of a classification system that helps keep adult material beyond the reach of children," Mr Smith said in a statement.

"With strong classification guidelines in place, an R18+ rating should result in violent games currently rated MA15+ in Australia being reclassified as adults-only, as they already are in many other countries."

A spokesperson for Mr Smith's office told ABC Technology the statement could be taken as confirmation that NSW has given the R18+ rating a green light.

"We abstained from the general thumbs up for an R18+ rating in Adelaide [last month] but said outside we suspect we would advise that we are... voting yes," the spokesperson said.

"We have done that. Think of this as finalising [and] formalising the support."

The lack of an R18+ rating means particularly violent or adult-themed computer games are either censored or banned in Australia, though Australia does have an R18+ rating for movies.

Gamers have argued the rating would protect children from games containing inappropriate material, while giving adult gamers a choice.

Mr Smith says he will work with attorneys-general from around Australia to develop the draft guidelines, which are expected to adjust the wording of the existing MA15+ category in order for it to be more restrictive.

'Violent impact'

The new guidelines are also expected to open up the R18+ category to allow games that have previously been banned due to "violent impact" - such as Mortal Kombat 9 and the uncensored version of Left 4 Dead 2.

South Australia has previously indicated it will also scrap the current MA15+ rating, meaning all violent games will be restricted to adults.

Mr Smith says it remains important that any proposal falls into line with a previous agreement to not dilute Australia's Refused Classification category.

A national telephone survey conducted by Galaxy last year showed 80 per cent of the 2,226 people contacted said they supported the introduction of an adults-only category for games.

The Federal Government has been advocating for an R18+ classification for some time.

Minister for Justice Brendan O’Connor says he is "delighted" that NSW is on board.

"NSW has decided to support what is not just a practical public policy, but a very popular policy," he said.

"The introduction of an R18+ classification for computer games will provide better advice to parents and help prevent children and teenagers from accessing unsuitable material.

"Once introduced, the new classification will also afford adults the opportunity to view material designed for adults."