The commission of inquiry into the August sinking of the Tongan ferry Princess Ashika has been adjourned for two weeks.

The inquiry, which began in Nuku'alofa on October 27, has heard damning evidence from a number of witnesses, including the vessel's captain, who last week said he was asleep for much of the fatal sailing and was awoken only five minutes before the ferry overturned and sank with the loss of 74 lives.

Captain Viliami Makahokovalu Tuputupu said he knew the Princess Ashika was unseaworthy but sailed anyway, because he relied on Tonga's Marine and Ports Division to state whether or not the vessel was safe to operate.

Capt Tuputupu told the hearing that on earlier sailings water had come through the vessel, which had many holes, local newspaper Matangi Tonga reported.

On a voyage in July crew had to puncture the side of the vessel to let water out and another incident saw the vessel stopping in open sea because the engine died, he said.

Passengers told the inquiry of their concerns about the corroded state of the ferry, of seeing water pouring into the cargo deck through gaping holes, of being asked to help "bail out", and of a complete lack of safety or emergency information being given.

John Jonesse, the New Zealand-born managing director of Shipping Corporation of Polynesia, who bought the 37-year-old ferry on behalf of the Tongan government, admitted he never looked into the state of the vessel's hull.

He said the ferry was in a good mechanical order when he bought it and that was his main concern.

Mr Jonesse will return to the witness stand on January 21, when he will have counsel to represent him.

The inquiry will resume on December 7 and is due to make its final report by the end of March.

The three commissioners are Supreme Court Justice Warwick Andrew, master mariner Michael Handfield, and naval architect Richard James.