The future of Sydney’s Brutalist icon, the Sirius building, is once again in serious jeopardy.

On Wednesday, NSW environment minister Gabrielle Upton announced that the Tao Gofers-designed social housing complex would not be granted heritage listing.

"My role is to decide whether the building has aesthetic value and, if so, whether that value is such as to satisfy [heritage value] at a state level," says Upton in a statement. "While the Sirius building is distinctive, in my view, it is not a landmark worthy of state heritage protection."

A similar decision was made in August 2016 by then heritage minister, Mark Speakerman. The NSW Land & Environment court, then, overruled this decision in a landmark legal battle, and ordered Upton to re-think the listing within 14 days.

The government’s rejection of a heritage listing follows close on the heels of Sirius’ inclusion on the 2018 World Monuments Watch. The list from the World Monuments Fund (WMF) recognises cultural and heritage sites that they consider to be facing “daunting threats” – whether that be from urbanisation, human conflict, climate change, natural disaster, or a lack of conservation opportunities.

Following the recent decision, a proposal for a $120-million apartment project becomes one step closer to fruition.

The Save Our Sirius foundation aren’t done fighting quite yet though.

"If there's one millimetre of space to take this back to court, we will," Shaun Carter, chairman of the Save Our Sirius foundation, told Fairfax Media.

"We will stay that course, even if that means we are arm-in-arm in front of bulldozers."