"It was quite an intense fire. The boat in the shed, the shed and all the equipment inside were destroyed," Mr Wasson said.
"We're not sure what sparked the fire, but it's being investigated."
Sharon Thomas and her husband Adrian live nearby in the Lyness Cottage Accommodation.
Mrs Thomas had been out of the house until 1.30pm, where she returned to find a police officer at the top of the road.
When she drove past the shed she saw it had been "gutted by fire".
"It was a big corrugated iron shed. There's really not much left of it - the roof's gone, and the sides."
Meanwhile, a Restricted Fire Season has been declared in Whangarei as warm, dry weather raises the fire risk.
Whangarei District Council imposed the restrictions from 12am today.
The restrictions apply to all land in the Whangarei District. Matakohe/Limestone and Rabbit Islands already have a permanent fire ban.
The restriction means permits are required for all open air fires, but permits will only be issued where suitable fire protection measures can be provided.