The clean-up's complete after a Navy ship spilled up to 300 litres of oil in Akaroa Harbour

The lubricating oil spilled from the frigate Te Kaha on Sunday afternoon - caused by a defect in one of the ship's oil coolers.

The Defence Force says although tidal movement means some of the oil may have spread - Environment Canterbury and the harbour authorities are satisfied with the clean-up and the vessel has been released.

The Navy says it regrets the incident and an investigation into the exact cause of the oil cooler failure will be conducted.