Tens of thousands of people have gathered for a climate change rally in Melbourne, in one of the largest demonstrations of its kind.

Rally organisers have estimated that up to 60,000 took to the streets, while Victoria Police said up to 40,000 were in attendance.

A climate change rally in Melbourne in 2006 drew 30,000 people.

Friday's rally was the first of several demonstrations planned across Australia for the weekend.

Loading

The demonstrations have been timed to take place ahead of United Nations climate talks in Paris next week.

Leaders will meet at the climate conference to discuss a new global climate agreement to limit greenhouse gas emissions in an effort to keep global warming under 2 degrees Celsius.

Melbourne march organisers hope those attending the meeting will heed the message of climate concern.

"The majority of Australians want action on climate change," said Geoff Cousins, chair of the Australian Conservation Foundation, one of the organising groups.

"People now realise this is not some theoretical concept.

"This is affecting their lives on a daily basis and they want something done about it."

Jacinta Morahan, a GP and activist with Anglesea Surf Coast Air Action, said she wanted to see action in Paris.

"The medical community has been clear in its message: fossil fuels are hazardous to health, climate change is hazardous to health," she said.

"So our representatives at the Paris climate talks, please don't mess this up."

Luke Hilakari, secretary of the Victorian Trades Hall Council, earlier said "thousands" of union members were expected to join the march.

"We know this is important, we know climate change is dangerous and we know there are great opportunities for us in new jobs," he said.

A series of similar rallies are scheduled for other capitals around the world over the weekend.

However in the wake of the November 13 terrorist attacks in Paris, police have banned the march planned for the climate conference host city.

Organisers had hoped as many as 200,000 people would have marched in the flagship event in Paris.