Havelock North fire service chief fire officer Rod Triplow said the fire burned a 1m hole in the roof.
"Some embers came out of the chimney, I think, and settled down on to the tiled roof shingles," he said.
"They started smouldering away and slowly burned a hole through the roof."
He said when the fire service arrived staff and patrons had already evacuated the building.
He said only the shingles were ablaze, with minimal water used or interior water-damage.
"There were a few embers dropped on to the ceiling Batts but there was plenty of room up there, so we could get up and deal to it pretty quick."
Mr Mair said there was no damage to the building apart from the cedar shingles.
"It is just a matter of fixing up the roof."
A temporary patch has been placed over the hole.
He said finding a roofer skilled in wooden shingles was "up to the insurance" and a thatched roof was not being considered "at this time".