In Australia it is illegal to sell a video game or movie that has not been classified by the Classification Board (formerly the Office of Film and Literature Classification - OFLC). 
Under the National Classification Code 2005 , games must be refused classification if they;
- depict, express or otherwise deal with matters of sex, drug misuse or addiction, crime, cruelty, violence or revolting or abhorrent phenomena in such a way that they offend against the standards of morality, decency and propriety generally accepted by reasonable adults to the extent that they should not be classified; or
- describe or depict in a way that is likely to cause offence to a reasonable adult, a person who is, or appears to be, a child under 18 (whether the person is engaged in sexual activity or not); or
- promote, incite or instruct in matters of crime or violence; or
- are unsuitable for a minor to see or play.
It is important to note that point (d) in the classification code explicitly states that any game only suitable for people over the age of 18, must be refused classification in Australia.
How removing R18+ changes the rating system.
The film rating system has the additional R18+ & X18+ categories. Both the R18+ & X18+ classifications are for "films (except RC films) that are unsuitable for a minor to see". X18+ classification also includes "films (except RC films) that contain real depictions of actual sexual activity between consenting adults in which there is no violence, sexual violence, sexualised violence, coercion, sexually assaultive language, or fetishes or depictions which purposefully demean anyone involved in that activity for the enjoyment of viewers, in a way that is likely to cause offence to a reasonable adult". It is important to note, that any film only suitable for people over the age of 18 must at least be given an 18+ rating 
Below are some key figures from the Interactive Australia 2009 report commissioned by the Interactive Entertainment Association of Australia. 
- The average age of an Australian gamer is 30 years.
- The average adult gamer has been playing for 11 years.
- 70% of parents in game households play computer and video games, 80% of these parents play them with their children.
- 78% of parents say an adult is present when games are purchased for their children.
- 92% of parents say they are aware of the games played in their homes.
- 75% of all computer and video games classified in Australia are G or PG (Classification Board).
- 63% of adults do not know that Australia has no R18+ for computer and video games.
- 91% of adults (including gamers and non-gamers) say Australia should have an R18+ classification for games.
To change the regulations and / or laws it is necessary that all State Attorneys-General agree to the proposed amendment, thereby allowing the inclusion of an R18+ classification to the legislation. It appears that some State Attorneys-General are in favour to amend the legislation. For example: “It seems inconsistent that in Australia, adults are allowed to view ‘adult only’ films which have been classified R18+ by the Classification Board, but not computer games with an equivalent high level content ... At the moment, Australia is out of step with the rest of the developed world on this issue.” Rob Hulls, Deputy Premier and Attorney General – Victoria.  However, the proposed amendment is being vocally blocked by the South Australian Attorney General, Michael Atkinson.
South Australian Parliament Building
It is unclear of the positions of the other Attorneys General. Michael Atkinson has stated "It is true that I am opposed to an R18+ category for interactive games, but I am one of at least four Attorneys so opposed."  At this stage no other Attorney General has publicly opposed the R18+ classification. 
 Classification policy Attorney-General's Department. Retrieved on March 18, 2008.
 National Classification Code (May 2005) Attorney-General's Department. Retrieved on March 18, 2008.
 IA9 - Key Findings Interactive Entertainment Association of Australia. Retrieved on March 20, 2008.
 PUBLIC TO BE CONSULTED ON CLASSIFICATION OF R18+ GAMES OFFICE OF THE ATTORNEY-GENERAL, VICTORIA. Retrieved on March 20, 2008.
 Atkinson Addresses R18+ Rating Kotaku. Retrieved on March 20, 2008.
 Victorian and ACT attorneys general say they support R18+; others admit no position. GameSpot AU. Retrieved on March 20, 2008.