The ABS has been accused of unlawfully discriminating against gay and gender diverse people by not counting them in the 2021 census in a complaint to the Human Rights Commission.

The complaint against the ABS and then Assistant Treasurer Michael Sukkar, by April Long and co-complainant LGBTIQ+ advocacy group Equality Australia, was lodged with the commission on Friday.

The complaint alleges several breaches of the Sex Discrimination Act because of a failure to ask about sexual orientation, gender identity and variations in sex characteristics, and the manner in which the 2021 census was conducted.

It also alleges Mr Sukkar and the ABS engaged in deliberate conduct that breached anti-discrimination laws.

Equality Australia’s Legal Director Ghassan Kassisieh says the census failed to properly count LGBTIQ+ people.

“The 2021 Census could have provided crucial information about LGBTIQ+ people to inform the response of governments and non-government organisations to better address our communities’ needs, particularly in health and social services,” Mr Kassisieh said in a statement.

“Instead, it failed to ask the right questions to properly count LGBTIQ+ people.

“The fact is we still don’t know how many LGBTIQ+ families there are in Australia, nor where they are located.”

The census also asked “insensitive and offensive questions” that assumed people were in a heterosexual relationship and at worst “rendered LGBTIQ+ people invisble”, Mr Kassisieh said.

April Long, who uses ‘they/them’ pronouns, and partner Kelly, said the census also failed to include cases where a family like theirs included two mothers.

“Our initial reaction was shock,” Long said. “It didn’t capture us, it made us feel invisible and it didn’t count us.”

Comment has been sought from the ABS.