Police believe an arsonist may be responsible for a fire that destroyed a popular aquarium in Mapua, near Nelson.
The fire gutted the Touch the Sea Aquarium building on the Mapua waterfront early on Thursday.
Detective John Nicholls says two smaller fires, which were discovered at the same time, are connected to the aquarium fire. Police are investigating a blaze at a tennis pavilion, and a fire in a rubbish bin.
Aquarium owner Murray Goss says the loss of the 11-year-old marine attraction is a huge blow, as it was popular with tourists and as an education centre for local school children.
The Fire Service was called to the Aranui Rd building at 3am on Thursday. At the height of the blaze, flames leapt through the roof of the aquarium building.
Eight fire trucks and 37 firefighters brought the fire under control within about 30 minutes.
However, the steel-framed and corrugated iron-clad building was destroyed and, with it, a gift shop and a landscape design premises.
Business owner Heather Cole says firefighters hosed the alleyway for two hours, saving her company's premises.
Fire crews worked to stop the blaze leaping a 2m-wide alleyway to a large former cool store building, which houses eight small retail businesses. None were damaged.