There has been a strong show of support in Greymouth for workers and contractors at the Spring Creek mine whose jobs are in doubt.
Owner Solid Energy says the plummeting price of coal internationally is making it harder to justify extracting it from underground, which is more expensive than open-cast mining.
The state-owned company last week suspended operations at its mine near Greymouth while it carries out a review, telling 240 workers it may be mothballed. About 130 contractors also work there.
On Tuesday, about 1000 people turned out for a march through the streets of the West Coast town, wearing T-shirts saying "Save Our Mine, Save Our Town" and shouting slogans attacking Solid Energy.
The company has so far refused to say when it will be able to give its workers an answer about their future.
Daryl Sweetman, a miner and one of the organisers of the protest, told Radio New Zealand's Checkpoint programme on Tuesday that Solid Energy has not kept workers informed.
"Kept us in the dark - they haven't told us anything. We're just sitting here not knowing what's going on. Some of the boys are getting sent up to do critical safety work, as they call it, but a lot of us are sitting at home wondering what the hell's going on."
Matt Birchfield was made redundant after the closure of the Pike River mine following a fatal explosion and now works at Spring Creek. He says he hopes the management will see sense and keep it open.
Vicky O'Neil, whose husband Ian works at the mine, says Greymouth has been struggling since Pike River shut and another big closure would further hit the local economy, affect property prices and see many retailers go out of business.
Spring Creek is one of the town's biggest employers.