Police from the Lake Macquarie Local Area Command are conducting inquiries into the cause of a suspicious boat fire.

Around 2am, emergency services were called to York Street, Teralba, following reports of an explosion.

Police attended the scene, where they found a boat on fire. The vessel, a Mariner 780 cruiser, had also been cut adrift from the wharf where it had been docked.

Personnel from Fire and Rescue NSW extinguished the blaze, with police now investigating the cause.

The fire has been deemed suspicious and officers are appealing for anyone with information of relevance to come forward.