A protester has allegedly been arrested after about 30 activists stopped operations at Takitimu coal mine in Southland.
Police are on scene at an area where the group from Extinction Rebellion are gathered.
Protest spokesperson Erik Kennedy said they were taking action because the mine's owner Bathurst Resources was planning an extension into a nearby council-owned forestry block and they believed local and central government were not doing enough to stop coal mining in Aotearoa.
Extinction Rebellion members have blocked the entrance to the mine.
Kennedy said they had provisions to last a couple of days.
Another protest spokesperson Adam Currie told Midday Report one activist had been arrested by police.
"We've had once activist arrested by police and we've got all sorts of activists locked on to various parts (of the mine), we have an activist on the lake, all sorts of people all around the mine (are) closing down this coal mine," Currie said.
Some protesters have climbed and set up hammocks on top of racks used to transport coal.
He said the group of protesters were "in it for the long haul".
Currie said the protesters had not had any contact with representatives from the Takitimu coal mine.