Protesters formed a "blockade" in the Port of Newcastle on Sunday in the third day of unrest, calling on the federal government to rule out new coal and gas mines and for a 78 per cent tax on coal and gas exports.

"Thousands of people from across the country have joined locals here to do what the Albanese government has failed to do - protect Australians from the worst impacts of climate change," she said.

"Despite the government's attempts to shut down our peaceful blockade, today we have successfully blockaded the world's largest coal port."

Ships temporarily stopped travelling through the area as a result of the protest, the port authority said.