Northern Territory Chief Minister Adam Giles is not responsible for overseeing the development of Port Meville, despite being officially responsible for "ports development", the Chief Minister's office says.

This is despite the $130 million ship-loading facility in the Tiwi Islands having been officially gazetted as "security regulated port" in 2014 by the Commonwealth Government.

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A spokesman for the office confirmed Mr Giles is responsible for overseeing "ports development" but said Port Melville was only "a piece of private infrastructure".

"The infrastructure in question is not classified as a port under NT legislation," the spokesman said.

"It's a piece of private infrastructure and is not subject to any specific 'port'-related approvals, licence, permit, etc.

"The only 'port' that is identified in legislation is Darwin."

When asked to clarify why Port Melville did not qualify as a "port", the spokesman said, "because it is private infrastructure by virtue of it being for the single purpose of transporting woodchips to a ship rather than being a multi-use, multi-purpose, fee for service commercial operation."

The NT Government has not yet announced which of its minister is responsible for the port, which was built in an environmentally sensitive area without any environmental approvals.

On Tuesday, the Federal Environment Minister Greg Hunt ordered the construction of the port would "be investigated as a matter of priority".

The following day, NT Environment Minister Gary Higgins said a "loophole" in planning laws meant there was no minister responsible for signing off on port developments.

In the past, Mr Giles has associated himself closely with the port, including visiting the port in March to announce an Indigenous lease agreement and inspect construction.

Under the Administrative Arrangements Order, which defines ministerial responsibilities, Mr Giles oversees "ports development".

The Commonwealth Department of Infrastructure and Regional Development issued a notice in April 2014 that declared Port Melville was intended for use as a "security regulated port".



It is a port that can take huge ships: Labor

Labor's infrastructure spokeswoman Natasha Fyles said it was nonsense to claim Port Melville was not a port.

"It's a port the Federal Government has signed off on giving it security classification so it can be used for defence purposes," Ms Fyles said.

Storage tanks at Port Melville, on the Tiwi Islands, which can store up to 30 million litres of diesel. ( Supplied )

"It's a port in every sense," she said.

"It's a port in the sense it's able to take huge ships.

"The owners of the port have been selling it as an oil and gas hub."

The Singaporean owner and developer of the port, Ausgroup, has been promoting it as a marine supply base for the offshore oil and gas industry.

The Australian Petroleum Production and Exploration Association (APPEA), the peak body for the Australian oil and gas industry, said no oil and gas operators were currently using or planning to use the facility.

Storage tanks which can store up to 30 million litres of diesel have been installed within an area that the NT Government has said in a report supports "many species not recorded anywhere else in the Northern Territory or in the world".

In the report, the Tiwi Islands are said to be the habitat of 38 threatened species of plants and animals.

Under Commonwealth law, projects likely to have a significant impact on a "matter of national environmental significance", must be referred to the Federal Government's Department of the Environment.

On Tuesday, Federal Environment Minister Greg Hunt ordered the construction of Port Melville "be investigated as a matter of priority".