An investigator says it's likely a professional gang of thieves is behind a spate of motorboat thefts in Canterbury.
Glynn Rigby, from the investigation firm Zavest, says it was hired to look into insurance claims following seven thefts.
He is aware of up to 11 thefts of boats valued between $20,000 and $90,000 which have hulls at least five metres in length.
Mr Rigby says the thefts began in late November, and it's possible the boats are being shipped offshore.
He says it's a wake-up call for owners to increase their security.
Mr Rigby says some of the boats were unsecured, while others were only secured by a chain and padlock, which thieves can easily cut through with boltcutters.
He says it's possible the police are unaware the thefts could be connected.