CANBERRA - The final investigation into the grounding of a coal carrier on Australia's Great Barrier Reef found fatigue was a major factor causing the accident.

The Shen Neng 1 struck Douglas Shoal off the central Queensland coast on April 3 last year, gouging a 3 km-long scar and spilling about four tonnes of heavy fuel oil from a ruptured fuel tank.

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The Australian Transport Safety Bureau (ATSB) on Thursday handed down its final report into how the ship ended off course.

The final report found the chief mate was fatigued and it affected his performance as he monitored the ship's position.

According to ATSB Chief Commissioner Martin Dolan, the ship's chief mate managed just 2.5 hours of sleep in the previous 38.5 hours as he supervised loading in Gladstone.

He said the grounding provided an important safety lesson for all seagoing vessels.

"Fatigue is one of the key safety risks facing seafarers, and watch-keepers in particular. Failure to manage fatigue can lead to loss of life, damage to property and damage to the environment," he said in the report.

The report also identified several other safety issues relating to the accident.

It found the ship's safety management system did not contain procedures or guidance in relation to the proper use of passage plans, including electronic route plans.

In the half-hour leading up to the grounding, there were no visual cues to warn either the chief mate or the seaman on lookout duty about the underwater navigation hazards directly ahead of the ship.

It also noted that at the time of the grounding, protections afforded by compulsory pilotage and active monitoring of ships by the Great Barrier Reef and Torres Strait Vessel Traffic Service ( REEFVTS) were not in place in the area off Gladstone.

Meanwhile, the ATSB has made four recommendations, two of them regarding the ship's management of safety issues and fatigue.

It also suggested action by the Australian Maritime Safety Authority to extend REEFVTS coverage to include the waters off Gladstone.

Dolan doubted such an accident could happen again, because the reef vessel tracking system, which monitors ship positions and notifies them if they veer off track, was now being extended to the seas off Gladstone.