A gigantic ship that sat stranded for months in a central Queensland port has been towed back out to sea and banned from Australia.  

The rusting KMAX Leader bulk carrier arrived at the Port of Gladstone in October 2023 and was set to take a shipment of coal to south-east Asia.

But mechanical issues saw it anchored at the port, one of the largest coal exporting terminals in the world, on the doorstep of the Great Barrier Reef, while repairs stalled for almost four months. 

The Liberian-flagged bulk carrier, measuring more than 200 metres long and almost 40m high, is now being towed back to the Philippines.

The Australian Maritime Safety Authority (AMSA) on Thursday banned it from re-entering any Australian port for 12 months.

AMSA national operations manager Greg Witherall said although it was a rare occurrence, the stranded ship posed a big safety risk, especially during cyclone season.

"If it were to break its mooring lines, or if it was to drag its anchor, it does pose a risk to the environment," he said.

"Especially in ports like Gladstone which are in the Great Barrier Reef."

During the time it was docked in the harbour, two cyclones crossed the Queensland coast.

Mr Witherall said when ship owners were not doing their job, the responsibility fell on local ports to protect workers and the environment during cyclones.

"It's not the ideal situation … the owners of the ports [have to then] ensure that there's adequate tugboats standing by," he said.

Mr Witherall said multiple notices were issued to the ship's Greek owner over the past five months about its failure to fix the issues and comply with international standards.

"The owner failed to engage with us, which left us in the dark," he said.

"[They initially] told us it would be eight to 10 days for repair [but] it took much longer than that."

The Gladstone Ports Corporation said, to ensure safety of the ship's crew, it provided support and a berth for the vessel as well as towage services.

The KMAX Leader is the 10th vessel to have been banned from Australian ports in the past year. 

Last year, Hong Kong flagged liquefied natural gas (LNG) tanker Cesi Qingdao was also towed out of the Gladstone port after being abandoned for a month.

At the time, Mr Witherall said the ship was fully loaded with 150,000 cubic metres of LNG.

It was released on December 23, beginning its journey being towed back to China, and subsequently banned from re-entering any Australian port for about six months.

Despite the two incidents, Mr Witherall said it was rare to see ships stuck for so long. 

"These vessels, they make money by carrying large amounts of cargo and so [being] disabled in a port for a long period of time financially hurts them as well," he said.

"All we're doing is implementing the minimum international standards, which exists to protect the lives of seafarers and our precious marine and coastal environments.

"Our view has always been [the standards] are not optional."

The ABC has contacted Universal Shipping Alliance and China Energy Ship Management.