It is the latest blow for the Christchurch rowing fraternity, which has been heavily affected by the earthquakes.
The Kerrs Reach boat shed, built in 1960, was yellow-stickered after the February 22 quake and had been used as a storage facility only.
But now the Canterbury Rowing Club - the oldest amateur sports club in New Zealand, founded in 1861 - has lost "thousands of dollars" worth of gear in the suspicious fire.
Alan Bain, president of the Canterbury Rowing Association (CRA), which represents all the local rowing clubs, said: "It's a big blow to the rowing community."
He said that three coaching motor-boats plus "an unknown number" of rowing skiffs would have been destroyed in the fire.
"We've got the secondary schools regatta at the end of April and we've lost those coaching boats. They are not cheap to replace and we need them now. We'll need to borrow boats and it will be a major problem," Mr Bain said.