The middle section of the Weld St building -- originally the Westland Dairy Co-operative store -- was the worst affected.
Fire investigators were at the site today to try to determine how and where the fire started.
The Hokitika Volunteer Fire Brigade was called about 6.30pm and it was later backed up by the Ross and Greymouth brigades.
Chief Fire Officer Harry Collett said the flames spread to the neighbouring machine shop of Evan Jones Construction Ltd.
Staff there were also cleaning up water in the workshop this morning.
However, the damage was mostly confined to the Signlink building.
Firefighters had to lift the roof to get to the flames, and at one stage they used a forklift to prise open a roller door to get access.
At least 20 firefighters were still working on the building at 8 o'clock last night, and had it under control an hour later.
Greymouth fire chief Lee Swinburn said the brigade had sent two appliances and a support van, which had returned home by 10pm.
St John paramedics and the police, managing traffic through a detour, were also on the scene, while spectators lined the neighbourhood streets.
Ms Stead said support from the community in the aftermath of the fire had been "awesome".
The business, which employs seven staff, would be back up and running from temporary premises as soon as possible.
Signs for the Hokitika Wildfoods Festival and Agfest were among the work to be completed.
The latest blaze comes only three weeks after fire destroyed parts of Westland High School. In October, the former Hokitika Motel complex was gutted by fire.
- Hokitika Guardian
