The protesters launched the action at the Kooragang coal export terminal near Newcastle following a protest at a neighbouring terminal the previous day.
In the previous action, police arrested 37 protesters who chained themselves to a train and rail tracks at Carrington terminal.
About 1,000 people marched to the terminal where about 100 protesters scaled or cut through fences to enter the rail corridor, bringing the busy coal terminal to a standstill.
Environment groups have said their protest is aimed at shutting down coal export operations at Newcastle, the world's largest coal port.
Joanne Ferris, a spokeswoman for the protesters group Camp for Climate Action said Australian governments were chained to coal.
"In the face of impending climate crisis the NSW government is expanding the coal industry, Australia's number one source of greenhouse emissions," she said.
"What we need is a just transition to a renewable energy economy.
"International examples prove that renewable energy will create tens of thousands of jobs for those most affected by climate change and those long-dependant on the destructive coal economy."
A spokesman for Port Waratah Coal Services, Graham Davidson, said coal loading was brought to a standstill for more than two hours on Monday morning.
"Kooragang terminal was brought to a halt for two hours due to safety issues."
Five protesters were cut from the coal conveyor belt by police, he said.