At about 5am on Sunday the May 13 there were three suspicious fires at Whenuanui Bay also known as Becks Bay in the Marlborough Sounds.
Two batches and a garage were extensively damaged by fire.
Police are appealing to the public for help with identifying the person or persons responsible.
They are particularly interested in any sightings of any suspicious persons noted in and around the Bay or on Queen Charlotte Drive during Saturday the May 12 or in the early morning of Sunday May 13, 2012.
Members of the public who have any information are asked to contact either the Picton Police on (03) 520 3120 or the Marlborough CIB on (03) 578 5279 or Crime Stoppers on 0800 555 111.