The Labor frontbencher who helped to set up an asylum seeker centre in Papua New Guinea concedes his party made mistakes in refugee policy.
But Richard Marles says the blame cannot be placed entirely on one side of politics or the other.
"Am I willing to say that Labor at that point in time (when in government) made some mistakes? Yes, I think we did," he told ABC TV on Sunday from PNG.
"But I also know this: we negotiated an arrangement with Malaysia which would have materially changed circumstances ... yet the coalition at the time opposed it.
"I think it's unreasonable to sheet all of the blame home to one side."
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Mr Marles also conceded the coalition's policy of turning back asylum seeker boats had been critical.
But he said the government had been "something of a one-trick pony".
"In those first couple of years, they were only focused on that and did not see the significance of finding third country resettlement options," he said.
He again argued the Turnbull government had all its eggs in one basket by relying solely on a deal with the United States to resettle refugees from Nauru and PNG's Manus Island.
Nevertheless, Labor does not want any of the refugees now on Manus Island to be settled in Australia when that centre closes in October.
Mr Marles said it was a difficult to come to that policy but it was important to hold firm to ensure the people smuggling trade could not restart en masse.
