It could be hours before a blaze south of Hamilton is fully extinguished.
Fire crews were called to Raynes Rd around 7pm on Thursday night to find a shed half full of haybales well ablaze.
At its peak, up to 50 firefighters were battling it.
A Fire and Emergency spokesman told Newshub crews are on standby, and will flip the hay bales over this morning to make sure the fire is snubbed out.
Meanwhile, fire crews in Greymouth are battling a house fire.
A Fire and Emergency spokesman said they were called to Buccleugh St around 3:40am.
Four appliances are at the house.
Everyone is accounted for, and there are no injuries.