According to O'Connor, the introduction of an R18+ rating in Australia would provide a means for parents to remove unsuitable material from children and teenagers.

"The Classification Board has been doing its job professionally and appropriately, applying the rules as they stand when making decisions on computer game ratings," O'Connor said.

"An R18+ rating for computer games and associated changes to the MA15+ category would reduce minors' exposure to images of gratuitous sex, violence or other adult themes."

O'Connor needs to secure unanimous support from the states if the change in classification laws is to go through.

The growing pressure on Porter comes as the nation's state attorneys-generals meet today for the Standing Committee of Attorneys-General (SCAG).