Legal counsel to a Papua New Guinea Defence Force inquiry says he believes evidence suggests the prime minister was behind a decision to fly a wanted man, Julian Moti, out of the country in October last year.
Mr Moti is wanted in Australia on child sex charges; he was secretly flown from PNG to the Solomons in October on a defence force plane.
The inquiry lawyer, John Kawi, says that the inquiry's principal role was to establish who ordered the Moti flight.
"I said that the sum total of all the evidence points to the prime minister, Sir Michael Somare. I said he should be investigated, and that quite possibly criminal charges should be laid against him."
In a statement, Sir Michael Somare rejected the the inquiry's proceedings as a "witch-hunt".