Sailors engaged in border protection operations have described the trauma of recovering bodies of asylum seekers and being told to wait to board vessels which subsequently sank.
One former sailor named only as Michael said his patrol boat was instructed to defer intercepting an unseaworthy vessel, returning later to find a long line of bodies in the sea.
"We fished them out for as long as we could, 'til we were full. And that wasn't uncommon," he told ABC television.
Another, Troy Norris, described the difficult process of recovering bodies which had been in the water for some time.
"Sometimes you'd go to pull these people in the boat and all you'd end up with is a handful of flesh. It'd just strip to the bone," he said.
Another, identified as Greg, described boarding an over-crowded vessel.
"You jump on and you can smell three days' worth of human faeces, you can smell vomit, you can smell diesel fuel, you can smell rotting wood, you can smell people, there are children screaming," he said.
Greg said he saw deeply disturbing behaviour by some asylum seekers, including an adult snatching a cup of water from a child. He intervened to stop the attempted rape of a boy by a man claiming to be his uncle.
"I became painfully aware that that child was only with him for the purpose of his own pleasure," he said.
All the sailors now suffer from post-traumatic stress disorder and have left the navy, saying they were not properly treated.
Their experience covered the peak period of asylum seeker arrivals under former Labor prime ministers Kevin Rudd and Julia Gillard.
In a statement to the ABC, Defence said that since 2011 it had implemented mental health screening for personnel assigned to border protection, with most dealing well with the pressures of this operation.
Reported rates of mental health-related symptoms were low, it said.
"Within the time available Defence is not able to report how many of those referred for follow-up went on to be diagnosed with a mental health condition," Defence said.