Inquiry probes border protection secrecy

Refugee advocates have cried foul over the lack of public information about border protection operations in their submission to a parliamentary inquiry.

A Senate committee is examining the Abbott government's secrecy over its Operation Sovereign Borders, especially the immigration minister's reliance on a public interest immunity to deny the upper house access to official documents.

The Senate has demanded the government disclose specific details about "operational matters" related to asylum seeker boat interceptions.

In response the government tabled transcripts of the minister's media briefings, citing national security reasons for keeping other information under wraps.

The Refugee Advice and Casework Service, in a submission to the inquiry, said it was concerned by the use of the public interest immunity.

The government's claim that release of the information would damage national security was overstated, it said.

But immigration department secretary Martin Bowles, in his submission, insisted disclosure would damage national security, international relations and defence.

The committee will hold a public hearing in Canberra next week.