The Tongan prime minister, Feleti Sevele, is scheduled to appear this morning before the Royal Commission into the sinking of the ferry, the Princess Ashika.
The inquiry into the disaster, and the loss of 74 lives, is resuming in the Tongan capital, Nukualofa .
The prime minister's appearance was postponed last week because he had to deal with the aftermath of Cyclone Rene.
Many of the witnesses who have already given evidence have said there was no due diligence undertaken before the ship's purchase.
It is expected Dr Sevele will be asked how much he knew about the ferry's condition before it was bought.
