A climate change protest off the coast of Australia's New South Wales State forced an inbound ship to turn back from the country's largest terminal for coal exports on Sunday, the port operator said.
New South Wales police said 170 protesters were arrested on Sunday for refusing to move from the shipping channel near the Port of Newcastle.
The port, some 170 km (105 miles) from the state capital Sydney, is the largest bulk shipping port on Australia's east coast.
A Port of Newcastle spokesperson said disruption due to the protest was "minimal" but that an inbound vessel "aborted due to people in the channel and has been rescheduled to come in".
Port operations would continue as normal on Sunday if police were able to keep the shipping channel clear, he said. Police said the harbour remained open despite "some serious disruptions".
The climate activist group Rising Tide, which organised the 50-hour protest that started on Friday, said the vessel forced to turn around was a coal ship.
Three people were arrested on Saturday after being removed from the water.
Climate change is a divisive issue in Australia, the world's second-biggest exporter of thermal coal and the largest exporter of coking coal.
A similar protest in November last year disrupted operations at the Port of Newcastle, forcing all shipping movements to cease temporarily.
(Reuters - Reporting by Sam McKeith in Sydney; Editing by Himani Sarkar and William Mallard)