An oil tanker hijacked by pirates last week in the South China Sea has been released, the Malaysian Navy says.

Malaysian Maritime Enforcement Agency (MMEA) deputy director-general (Operations) Ahmad Puzi said the crew was released following negotiations between the navy and the hijackers of the oil tanker, Bernama news agency reported.

It says eight hijackers fled the Orkim Harmony ship in a rescue boat late on Thursday. The vessel is now being escorted to a Malaysian port.

All 22 crew members were safe. However, one of them was slightly injured.

The tanker disappeared off the coast of Singapore on 11 June. Reports said it was taken by Indonesian pirates armed with pistols and machetes.

Malaysian navy ships and aircraft are now hunting the fleeing pirates, the authorities say.

The tanker, which was laden with 6,000 tonnes of petrol, worth RM21 million, was reported missing at 8.57pm last Thursday while on its way to Kuantan Port from Malacca.

The vessel, owned by Magna Meridian Sdn Bhd, was carrying 22 crew on-board, comprising 16 Malaysians, five Indonesians and a Myanmar national.