There is controversy over a $130 million deep sea port in the Northern Territory, after claims that the project went ahead despite having no environmental approval.

Reports say neither the NT nor Federal Government environment departments ticked-off the environmental credentials of Port Melville, which is now open for business on the Tiwi Islands.

The company behind the port – Singapore-based firm Ausgroup – says it hopes the hub will be used as a marine supply base for the offshore oil and gas industry, and to service US and Australian military vessels.

The site features about 30 million litres of diesel fuel storage tanks, located in an area known for its sensitive, unique and untouched ecology.

Northern Territory Environment Protection Authority (NTEPA) says “gross deficiencies” in existing laws left it powerless, allowing companies to ignore any of it recommendations.

Federal Environment Minister Greg Hunt has ordered an immediate investigation.

An in-depth ABC report alleges the project could be in breach of the Environmental Protection and Biodiversity Conservation (EPBC) Act, which carries fines of up to $8.5 million in some cases.

But the EPBC Act says assessments are only necessary under certain circumstances, like when a development could significantly impact a “matter of national environmental significance”.

Port Melville general manager Roger Smith claims the project did not need approval under the EPBC act because it was an upgrade rather than a new build.

“Based on available information, the development is believed not to have a significant impact on any matter of national environmental significance,” Mr Smith told News Corp reporters.

“(Port Melville) has never ceased to be an operating port.”

The Northern Territory Government has previously praised Ausgroup and its work at the Tiwi Islands, which is the location of a budding forestry business owned by local Indigenous groups.

Port Melville is seen as a gateway to get Tiwi Island timber products to mainland Australia and around the world, and is central to the future employment and economic prospects of the Tiwi Islanders.

The Port Melville redevelopment project was started in 2010 by a subsidiary of Singapore-based Ezion Holdings, whose sub-leases were later bought-out by a subsidiary of AusGroup.

AusGroup executive ­director Larry Johnson, a previous employee of Ezion, has been with the project from the start.

“We are not developing a greenfield site here; we are operating a site that was ­already approved. We are working within the same footprint as the previous ­operations.

“The port was ­approved before; we are just making sure that it’s approved again.”

He said claims Port Melville was “open for business” were incorrect.

NT Environment Minister Gary Higgins is yet to comment on the matter.

Indigenous Affairs Minister Nigel Scullion has been pressed for details on the environmental approval process by NT Labor senator Nova Peris .

“My instinct is that invariably bunkering facilities are actually subject to standards rather than environmental impact statements,” he said, while taking other inquiries on notice.