Defence has no security concerns about the long-term lease of the Port of Darwin to a Chinese-owned company.
The three arms of the defence force, the Australian Signals Directorate, the Defence Security Agency and Defence's strategic policy division were all consulted about the 99-year lease to the Landbridge Group.
"No part of defence had a concern from a security perspective," Defence Department secretary Dennis Richardson told a Senate estimates hearing in Canberra on Wednesday.
The NT government has signed a $506 million deal with Landbridge to lease the port and facilities for 99 years.
Labor wants the deal examined by the Foreign Investment Review Board while some security analysts say the implications for national security need to be considered.
Mr Richardson said Darwin was a commercial port, not a navy base.
Under a licence deal signed in May, the navy had assured access for a certain number of days.
It would be illegal for the company to just close the port.
"Quite apart from that, we have some over-riding powers under the Defence Act so that's just not a possibility," Mr Richardson said.
Defence Minister Marise Payne said the deal wasn't subject to FIRB review or approval.
"It doesn't actually qualify under the guidelines," she said.
