JOHN Howard yesterday defended the Australian navy despite evidence it failed to spot the refugee boat, dubbed Siev X, that sank and drowned 353 asylum-seekers.

Dismissing reports of the tragedy and subsequent Senate inquiry as 'outrageous', the Prime Minister said the navy had fulfilled its moral obligations.

'The navy did everything that could reasonably be expected and the continued attempt to implicate them, and in some way to imply they are responsible for this tragic accident, I think it's quite appalling,' Mr Howard said.

His comments follow a report in The Weekend Australian that a navy P3 Orion plane had flown over the area where survivors were clinging to debris of their vessel on October 19 and 20 last year.

The patrols were not sent to the area specifically to search for the Siev X, despite unclear intelligence that an overloaded vessel was headed for Christmas Island.

News that planes searched near Indonesian territory appears to contradict testimony by incoming navy chief Rear-Admiral Chris Ritchie, who said the surveillance focused on Christmas Island. The man who first cast doubt on the affair, former diplomat and visiting Australian National University fellow Tony Kevin, said the new details reinforced his fears.

'If one was serious about trying to find the boat, one wouldn't simply maintain one's regular search pattern involving just one pass over a huge area,' Mr Kevin said.