This article is more than 5 years old

This article is more than 5 years old

The head of the department that oversees the Australian Border Force is initiating potentially costly legal proceedings at taxpayers’ expense in a bid to keep secret a single document about the federal government’s asylum seeker turnback operations, despite some of the material being publicly available.

In July, customs – now part of the immigration department with the creation of the Australian Border Force – was forced to make public material outlining the legal processes, policy framework and operational objectives involved in conducting asylum seeker turnback and towback operations.

The agency had previously refused to release the material, claiming it would damage national security. It formed part of a freedom-of-information request from Guardian Australia for documents including ship logs and orders to conduct turnback operations.

The outgoing Australian information commissioner, John McMillan, ruled in his final decision for the commission that part of one document should be released because it would “add to public understanding of how a difficult and sensitive function is discharged within government”.

Details about asylum seeker turnbacks to remain secret, commissioner rules Read more

It was the only material out of 15 documents requested that McMillan said should be released. He ruled that there was no public interest in the release of ship logs and requests and orders relating to the turnback operations.

But the secretary of the immigration department, Michael Pezzullo, is now launching an appeal in the administrative appeals tribunal to fight that ruling.

The case is likely to throw the spotlight on secrecy surrounding asylum seeker turnback operations. The federal government has adopted a policy of refusing to confirm or deny when an asylum seeker vessel is intercepted and turned back to another country.

The appeal is being run on a particularly technical point of law. Under freedom of information laws, when an agency invokes national security as an exemption, the information commissioner must consult the inspector general of intelligence and security before it can be released.

The agency argues that McMillan “mistook” its submissions about whether the whole document fell under that provision, and should not have made a ruling on any of it without taking evidence from the inspector general.

The case may be a landmark ruling on how national security freedom of information cases can be decided, and may lead to the inspector general having to provide advice on national security implications of the federal government’s asylum seeker policies.

The information commissioner may also be able to seek standing in the case, although the office is currently without a dedicated freedom of information commissioner.The privacy commissioner, Timothy Pilgrim, has assumed the additional role of acting information commissioner.

An initial conference is scheduled at the administrative appeals Tribunal in October.