A loud explosion that shook Runanga and Dunollie on the West Coast early this afternoon was traced to Department of Conservation blasting on the Point Elizabeth Track.
DOC confirmed it had been doing blasting on the track this morning.
A host of people in the area reported hearing a loud, booming noise. The blast was apparently heard as far away as Dobson, Kokiri, Cobden and Ngahere.
Dunollie Store owner Gwen Hislop said it was very loud and she listened out for the sound of emergency services afterward, but was surprised to hear nothing.
Ms Hislop said it sounded like it might have come from the direction of Rapahoe, though it was difficult to tell.
Social media was buzzing with reports of the suspected explosion. Local woman Sandra Gibbens said in a message to the Greymouth Star Facebook page that she heard a "really big bang" in the area, which she said quite a few people had heard and felt.
Runanga Volunteer Fire Brigade chief fire officer Gavin Gibbens also heard the boom but had no idea what it was.
Solid Energy spokesman Bryn Somerville said they had not been blasting and did not know where the explosion had come from.