A stable block at the Omoto Racecourse was razed by an early morning arson early today.
The Greymouth Volunteer Fire Brigade was called about 3.50am after a passerby on nearby State highway 7 noticed flames.
Fire chief Lee Swinburn said the stables were well ablaze when two fire appliances and a support vehicle arrived at the scene 10 minutes later.
Daylight showed that the gable end of the corrugated iron stables, built between the 1970s and 1980s, was all that remained standing on the site, just across the railway crossing.
"It had obviously been going for some time before we were notified," Mr Swinburn said.