Arrests after climate protest chaos on Melbourne bridge

Three people have been arrested after a protest caused traffic chaos on a major Melbourne bridge.

Extinction Rebellion members parked a truck on the West Gate Bridge, climbed on top of it and unfurled banners reading, "declare a climate emergency" and "climate breakdown has begun" about 7.45am (local time) on Tuesday.

Police used a cherry picker to make the arrests and lower the trio down safely at 9.45am after they refused to get off the truck.

It is expected each will be charged with public nuisance and obstructing a roadway.

No one was injured during the incident.

All inbound lanes reopened by 10.15am but VicTraffic warned significant delays remain on the West Gate and Princes freeways, M80 Ring Road and the surrounding area.

Three lanes on the city-bound side of the bridge had previously been blocked and delays stretched back about 30km.

Roads in Yarraville, Footscray and West Melbourne were also affected by the congestion.

Police say the group also lit a flare when on the truck.

In a livestream video posted to the group's Facebook page, the three protesters called for government action on climate change.

"This is a climate and ecological emergency and our actions every day impact the habitability of our planet for ourselves and for generations to come," activist Violet CoCo said.

"We're extremely committed to non-violent direct action but we are committed to sounding the alarm on the climate and ecological emergency.

"We are asking the government and all levels of society to declare an ecological emergency and to act on that emergency as soon as possible."

Extinction Rebellion describes itself as a non-partisan movement that uses non-violent action to demand governments take action on climate change.

Its previous demonstrations have included dozens of people blocking the Montague St off-ramp during peak hour and a man climbing the spire of the Arts Centre Melbourne last year.

Ms CoCo, 33, was previously jailed for 13 days after blocking a lane of the Sydney Harbour Bridge during morning peak hour in 2022.

That incident also involved three people climbing on top of a truck, lighting flares and livestreaming.

Ms Coco was joined on the West Gate Bridge by Brad Homewood and Joe Zammit, according to the group.

Extinction Rebellion said in a social media post the protest was designed to coincide with the Association of Southeast Asian Nations summit in Melbourne.

It wants Australia to declare a climate and ecological emergency at the conference and is calling on other ASEAN leaders to do the same.