Extinction Rebellion demonstaters have blocked the main entrance to the Queensland parliament and strewn the area with fish carcasses and banners.
The protestors, who began demonstrating about 7.30am on Wednesday, want government action on climate change to get to net zero emmissions.
Activist Rene Wooller says the state government should offer state pensions to coal miners to leave the industry.
"The Queensland government needs a climate transition plan that doesn't exclude coal miners," she said in a statement.
"If a politician can get a pension for leaving politics, why can't coal miners get a pension for leaving coal."
The protestors also want action to save the Great Barrier Reef, after the International Union for the Conservation of Nature (IUCN) listed it as "critically-threatened".
IUCN World Heritage program director Tim Badman said the extent to which climate change has damaged the reef was unprecedented.
Coral ecology expert Dr Selina Ward said there was enough coral left to save the reef if emissions were dramatically reduced, but further work was also needed.
"But we must act now, we have no time to wait," Dr Ward said.
"We certainly have no time for new coal mines and new port expansions."
One activist was arrested after scaling the parliamentary annexe and refusing to come down.
While the gates to the annexe remain closed, MPs were still able to enter the building for Wednesday's sitting of parliament.