A truck fire after a tank explosion in Petone is expected to cause delays to rush hour traffic.

A Fire Service spokesman says the truck and trailer was well ablaze on Waione St, Wellington, at 4.30am.

The fire had since been put out and no-one was hurt, but Waione St is expected to remain closed for two hours. Diversions are in place, which will affect the 130, 81, 84 and 85 bus routes.