The burnt out pirate ship at Splash Planet.

A "legendary" Hawke's Bay structure has been destroyed by fire.

The pirate ship at Hastings' Splash Planet fun park, which has been a favourite children's play area for decades, was deliberately torched on Sunday morning.

A fire crew spent almost two hours battling the blaze of the 20 metre ship, part of the original park which opened in 1967.

Senior fire officer Bryan Dunphy said the ship was well ablaze when firefighters arrived.

The fence around the Grove Rd park had been cut so the fire was being treated as suspicious, he said.

Splash Planet manager Peran Hutchings said the staff were "pretty gutted".

The ship was a play structure in the part of the park that was formerly Fantasy Land.

It had become an "iconic feature" in Hawke's Bay, Hutchings said.

He wanted to thank the Fire Service for being prompt and containing the blaze, which prevented it from spreading and causing more damage.

Fire safety and police were investigating.