A house has been razed and a boat, car and whitebait stall damaged in a rash of arsons near Motueka overnight.
Police say a house was destroyed and two vehicles were engulfed by fire in three separate blazes.
Earlier in the evening a whitebait stall was reportedly set alight just before 6pm.
Police are also investigating a burglary overnight in the Riwaka area, which they believe is connected to the arsons.
Police said the house on Umukuri Rd was razed in a blaze that ripped through the property about 2.30am.
The only person in the house managed to get out uninjured.
A boat was set alight at 2am and a car was torched at 3.18am.
Police said a 31-year-old man had been arrested and was helping police with the investigation.
The Nelson CIB was also continuing to look into the suspicious blazes.