An asylum seeker says the burns on his hands were caused by Australian Navy personnel holding his hands to hot parts of a boat engine. Prime Minister Tony Abbott, asked why the government could not settle the matter by releasing navy footage of the operation, said he did not want to ''do anything that would cast aspersions on the professionalism of our naval and customs personnel''. And Defence Minister David Johnston dismissed the latest claims as ''hearsay, innuendo and rumour'' in an angry rebuke of the ABC's reporting of the matter as he called for an investigation into the national broadcaster. Fairfax believes a standard ''quick assessment'' has been carried out, similar to initial inquiries conducted when Australian Defence Force personnel are involved in incidents while fighting overseas. This is likely to have involved informal interviews with members of the navy boarding party that undertook the asylum-seeker boat turn-back about January 6.

Defence Minister David Johnston. Credit:Alex Ellinghausen The government has previously admitted that Australian authorities have not spoken with the asylum seekers. Immigration Minister Scott Morrison said on Thursday: "Endlessly repeating and reporting unsubstantiated and wild allegations doesn't make those claims any more credible or deserving of further review. Illustration: Ron Tandberg. That is why the government will continue not to dignify or give credibility to such unsubstantiated allegations despite hysterical calls to do so. Border Protection Command has internal procedures in place to ensure they are in a position to provide the assurances they have made to the minister regarding the conduct of personnel involved in any operation.

"It is not operational practice for video footage to be taken on all operations. When and where video is or is not undertaken is a matter for the operational agencies.'' On Thursday, Fairfax revealed a detailed account by Sudanese asylum seeker Yousif Ibrahim Fasher, who said he had seen navy sailors force the hands of three asylum seekers onto exhaust pipes, causing burns. Those allegations, originally aired early last month, have been repeatedly denied by the government as well as the Chief of Navy, Vice-Admiral Ray Griggs. The Chief of the Defence Force, General David Hurley, has also dismissed claims of misconduct by defence personnel, though he did not go into any specific allegations. Mr Abbott sidestepped questions about whether he backed Senator Johnston's call for an inquiry into the ABC, indicating he was satisfied by the criticism aired by the broadcaster's Media Watch program on Monday.

Mr Abbott said there was still no evidence that credibly cast doubt on navy actions. Asked whether the government should release any video it had of the interception and turn-back of the boat, Mr Abbott said that might help people smugglers and therefore hamper the job of stopping asylum-seeker boats heading to Australia. ''I don't want to do anything that might complicate that task of stopping the boats and frankly I don't want to do anything that would cast aspersions on the professionalism of our naval and customs personnel,'' he said. ''I have nothing but respect for them … and I have seen nothing that credibly casts any doubts on that professionalism.'' Senator Johnston said the navy had been ''maliciously maligned'' by the ABC's coverage of the matter, dismissing the public broadcaster's apology as ''weasel words'' from its senior management. Loading

''I have not said much because, I have to confess, I was extremely angry. I required some time to cool off,'' Senator Johnston said. Professor of International Law at the University of Sydney, Ben Saul, said under international law, Australia had an obligation to impartially investigate allegations of torture or other cruel, inhuman or degrading treatment.