Adam Bennett, Sydney – A NSW coroner hearing an inquest into the death of one of five Australian journalists in East Timor more than 30 years ago has agreed to hear some evidence in secret.

Deputy State Coroner Dorelle Pinch today heard a federal government application that future evidence from commonwealth officials, and subpoenaed documents from the Defence Signals Directorate (DSD), be heard in camera at the inquest into the death of cameraman Brian Peters.

Mr Peters and four other newsmen, now known as the Balibo Five, were killed near the town of Balibo during Indonesia's 1975 occupation of East Timor.

Making the application on behalf of the commonwealth, Alan Robertson SC said the DSD documents and parts of the evidence to be given by future witnesses – including former intelligence officers – would be sensitive to Australia's national security.

Mr Robertson referred to two statutory declarations from acting director of the DSD, Edward Clive Lines, in which the intelligence chief said disclosure of the evidence in an open court would "seriously prejudice Australia's national security and defence interests".

"The submission is that some of the evidence will be able to be given in an open court," Mr Robertson said. "Not that the information be withheld entirely."

The application was supported by counsel assisting the coroner, Mark Tedeschi QC, but opposed by counsel for the Peters family, John Stratton.

"These events occurred 30 years ago and... there has been a 30-year history of deceit and cover-up in relation to the true story of how the Balibo Five were killed," Mr Stratton said.

"Thirty years after the events, this material can only be of historical interest. "Any disclosure of material would not hurt the national interest."

Ms Pinch said she was "mindful" of Mr Stratton's concerns, but ruled in the commonwealth's favour. "I am satisfied that the prejudice to Australia's national security and defence interests is real and current," Ms Pinch said. The inquest continues.