Gay solidarity supporters protest on Oxford Street Paddington eventually arrested in Taylor Square.

Pride … gay activists protest in Oxford St in 1978. Photo: Kevin Berry

A MUSEUM dedicated to Sydney's gay and lesbian history is as important as institutions that preserve Jewish history and Australia's military past, says a leading broadcaster and gay rights activist.

''I'd compare it to the Australian War Memorial,'' said Julie McCrossin. ''It would deepen personal relationships and community understanding.''

Ms McCrossin campaigned for gay rights in the 1970s and said: ''My memory of that time was you had an illness, it was against God's will and it was unlawful for men and, by implication, for women.''

Julie McCrossin, left, curator Nick Henderson, centre, and CEO Michael Rolik are preparing for the openning of a new Mardi Gras museum in Darlinghurst.

Julie McCrossin, left, curator Nick Henderson, centre, and CEO Michael Rolik are preparing for the opening of a new Mardi Gras museum in Darlinghurst. Photo: Janie Barrett

She was speaking before the opening on Tuesday of a temporary exhibition charting the history of Sydney's Gay and Lesbian Mardi Gras from its origins in 1978.

At the time, homosexuality was a crime in NSW.

The brutal treatment of protesters by police sparked a campaign that led to the decriminalisation of male homosexual behaviour in 1984.

Tv and radio personality Julie McCrossin models a t-shirt for the Wear IT With Pride campaign.

"It would deepend personal relationships and community understanding" ... Julie McCrossin. Photo: Simon Alekna

The exhibition, in Oxford Street, Darlinghurst, will be opened by the lord mayor of Sydney, Clover Moore, and features a documentary about the mardi gras's origins as well as photos and parade costumes.

The Schwules Museum in Berlin and the GLBT Historical Society Museum in San Francisco are considered the only two permanent gay and lesbian museums in the world.

David Wilson, a director of Sydney Mardi Gras, leads a committee that is planning the museum and has identified the T2 Building at Taylor Square as a potential site.

Cr Moore said she supported the idea of commemorating the history of the gay and lesbian community.

''The temporary museum being provided by the city during mardi gras will help gauge public support for a permanent museum," she said.