Prime Minister Tony Abbott has refused to confirm whether a boat load of asylum seekers has been returned to Vietnam, saying that secrecy was in the national interest.
An asylum-seeker boat was spotted off Western Australia's north coast last week near Dampier. But the federal government has declined to confirm whether the passengers have been sent back.
Mr Abbott said his government was acting in the national interest and not "running a shipping news service for people smugglers".
"We haven't felt the need to big note ourselves," Mr Abbott told reporters in Sydney.
The previous Labor government had spent too much time talking about itself and not enough time getting on with the job of border protection, he said.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
Representatives of the Vietnamese community in Australia have criticised the asylum seekers' return.
"I have a great fear for their safety," Victorian president of the Vietnamese community, Bon Nguyen told ABC Radio.
Australian Greens senator Sarah Hanson-Young demanded the government explain what happened to the people.
"Handing these people directly over to the Vietnamese government constitutes refoulement, which is a breach of the refugee convention," she said in a statement.
There had been an increase in people fleeing Vietnam over religious persecution, particularly Christian minorities, she said.
