A derelict Australian oil platform north of Darwin could cost taxpayers up to one billion dollars, says independent Senator Rex Patrick.

The Northern Endeavour is a floating oil production storage and offtake facility in the Timor Sea oilfields, 550 kilometres north-west of Darwin.

Responsibility for the Northern Endeavour fell to the federal government last year after the safety authority found Structural issues exist due to advanced corrosion in multiple areas onboard