Hundreds of people have shut down traffic on the Commonwealth Avenue bridge in protest of climate change inaction.
An estimated 500 people have taken part in protest movement Extinction Rebellion's demonstration in Canberra.
The protest march started from Albert Hall, with demonstrators moving slowly northward across the Commonwealth Avenue bridge.
Leading the procession was a group of performance artists known as the Red Rebels, whose red-coloured garb is meant to signify the blood of the children who will die as a result of climate inaction.
Later, protesters were seen lying down - an action known as a "die-in" - on southern apron of the bridge, just metres from the entrance to Floriade, as three bagpipers played a lament.
Protesters say they were lying down on the road to simulate public apathy on the issue and the deaths of people due to climate change. The protesters were then urged to "rise up" from the roadway and continue the protest.
ACT police were expected to close off the bridge to traffic from 11am to 11.30am for the march, but protesters remained on the bridge for almost 30 minutes longer than expected.
The protesters then veered off the bridge and rallied beside the lake between the National Capital Exhibition and Commonwealth Avenue.
In other capital cities, Extinction Rebellion is emerging as one of the more militant climate change protest organisations, chaining themselves to steel barriers in the middle of Brisbane's CBD and marching nude through the centre of Melbourne.
Extinction Rebellion's co-founder, NSW organic farmer Roger Hallam, is under arrest in the UK for breaching his bail conditions. He had previously been arrested suspicion of conspiracy to cause a public nuisance before a day of disruptive action planned at Heathrow Airport.
ACT protester Pete O'Rourke said more action was needed to prevent global warming.
"Australians have everything to lose from continued inaction, but politicians continue to ignore our safety in favour of the interests of big business and their own short-term political gain," Mr O'Rourke said.
"Today we're telling them: enough is enough."
Extinction Rebellion ACT is planning another protest - a "ride in to die in" - on Friday morning. Supporters will gather with their bicycles at the Ainslie Football Club around 7.45am then ride slowly en masse down Northbourne Avenue into the city.
The group then plans to have a mass "die in" at an undisclosed location.