Port protesters take to water as Peter Garrett performs

Thousands of protesters have descended on the world's biggest coal port to hear prominent musicians perform at what has been billed as "one of Australia's most significant" climate protests.

Anti-coal demonstrators and supporters are making their way into the water at the Port of Newcastle as part of a mass flotilla and protest on Horseshoe Beach.

Climate protesters remained on the water overnight and into Saturday after paddling out in kayaks on Friday as part of the planned three-day blockade in the coal-rich NSW Hunter region.

There is a festive, determined and hopeful feel among camp goers, Rising Tide organiser Alexa Stuart said.

"We have made our voices heard in a way that our government cannot ignore," she said.

"This is one of the most significant climate protests in Australia's history at the world's largest coal port.

"I hope our government hears the people and their demands that they stop approving new coal and gas projects and start investing in the Hunter region, in new industries and support for workers."

Midnight Oil frontman and former environment minister Peter Garrett along with musicians including John Butler and Angie McMahon have taken to the stage to perform on Saturday as part of an associated festival.

"It just shows how widespread the concern of the climate crisis is that famous people, everyday Australians, young people, old people, are all here together, united to send a message to the government," Ms Stuart said.

Garrett performed songs including band hits Blue Sky Mine and Tin Legs and Tin Mines.

He slammed the "overreach" from authorities, including the NSW government, for attempting to stop the peaceful protest event.

"Is the threat to the wellbeing and the peace of the Hunter region to be found in a group of citizens exercising peacefully their democratic rights or is it to be found in continuing to export a material which is going to blow the world up in a furnace?" Garrett told the crowd.

"Let's get our perspective sorted out here please, leaders."

Court challenges that eventually allowed the event to proceed previously heard some protesters might seek to be arrested to attract publicity.

A similar event in 2023 resulted in 109 arrests when protesters remained in the water beyond the advised period, attracting global attention.

NSW Police said they had adopted a "zero-tolerance approach to actions which threaten public safety and the safe passage of vessels".

There is a large police presence at the event with officers escorting coal ships through the harbour and policing the water.

"We're able to go into the water, but the shipping lane, which is marked by two buoys, that's where the police are monitoring the water, preventing us from going into that section of the water," Ms Stuart said.

Event organiser Rising Tide wants to end new coal and gas approvals and a 78 per cent tax on coal and gas exports to help fund the clean energy transition.

The Greens used the event to announce activist and law student Luc Velez as the party's candidate to take on Environment Minister Tanya Plibersek in Sydney at a federal election due by May.