Redhead Surf Club escaped damage overnight when an adjoining toilet block was rocked by an explosion.
Police have established a crime scene after the explosion destroyed most of the roof and ceiling, and also blew out a window.
President of Redhead Surf Club Mike Mckey says this isn't the first time the club has been subjected to vandalism with the club previously dealing with graffiti vandalism.
"It's disappointing that these things happen, even though the surf club wasn't damaged, it's a public building, ultimately the cost has to be borne by the public and the rate payers and that's pretty disappointing."
The club are working with police to review CCTV footage to help identify possible suspects.
