Tony Burke has let slip the government has long held advice showing the practice of turning back asylum seekers does not work, undermining his own party's determination to do so with the Oceanic Viking refugees.

Mr Burke, the Minister for Sustainable Population, referred to the advice when trying to discredit the opposition's plan to turn back boats at a debate hosted by the National Press Club. According to Mr Burke, intelligence received by Labor upon taking office in 2007 said: ''If you try to turn a boat back, no country will take them.''

The advice was supplied by the Australian Defence Force's Northern Command and would have been known to the Howard government, he said.

Pressed on why the former prime minister, Kevin Rudd, would then have ignored such advice to send 78 asylum seekers back to Indonesia last year, Mr Burke said he was not privy to the rationale. ''I was not in the room. I was not part of that decision-making process,'' he said.

Such advice is significant because had the Rudd government followed it, an embarrassing diplomatic stalemate could have been avoided.