A large rubbish fire in Solway Showgrounds, Masterton, on Saturday night was a case of arson, according to Masterton Fire Service.
The fire was reported just before 6pm, having been spotted by someone driving past along Ngaumutawa Rd.
"It would have been highly visible," station officer Richard King said .
Mr King said the fire was caused by an unknown person setting alight a large pile of rubbish at the back of the showgrounds.
The pile of rubbish included branches and fenceposts and was about 4m by 4m in size.