"(The guidelines) represent a commitment to recognising the full diversity of people in Australia..." Mark Dreyfus said.

Intersex Aussies will now be officially known as gender 'X'

X WILL now mark the spot for those Australians who consider themselves in the grey area neither male nor female.

New national guidelines introduced by the Commonwealth Government mean personal records will offer the gender choice of M, F or X.

The X may be used for those who do not consider themselves male or female, whether because they are walking the path to change gender or those who are intersex or "gender diverse".

Those born with biological differences or combinations to the standard male and female physical attributes may consider themselves intersex or gender neutral.

The bureaucratic changes come into place from July 1.

Advocacy groups welcomed the change.

Australian Transgender Support Association of Queensland represents those changing or who have changed their gender.

Secretary Kristine Johnson told APN the new option for gender was "absolutely wonderful".

Ms Johnson said for the transgender or trans community, it was "breathing room" as they considered who they were.

"The marker X has been used extensively in New Zealand, particularly on their passports which were male, female or X marks the spot," he said.

"Like anything that goes through, it can only be improved upon."

Ms Johnson said some along "the spectrum of people with gender issues" may not be supportive, but said the conversation was needed.

Federal Attorney General Mark Dreyfus said it was a "practical improvement" for those who were transgender, intersex and gender diverse.

"(The guidelines) represent a commitment to recognising the full diversity of people in Australia and ensuring all people are treated with respect by the Australian Government departments and agencies," he said.