A firefighter at the scene said the blaze was almost identical to one set on grandstand seating on Friday night, and appeared to be in the same, upper left, tier.
It was unclear whether accelerant had been used, but police and fire investigators were looking at both incidents, he said.
Clutha District Council chief executive Steve Hill, who attended the incident on behalf of the council, said although ‘‘annoying’’, minimal damage appeared to have been done, and he praised the brigade for its quick action.
The council provides annual grant funding to the South Otago A&P Society, which owns and maintains the property.