Tonga's Prime Minister and other cabinet ministers have been summoned to give evidence at a Royal Commission of Inquiry into the sinking of the ferry Princess Ashika.
Seventy-four people died when the Princess Ashika capsized and sank in August last year.
An investigation into the tragedy resumed this week in Tonga, with New Zealand marine engineer David Shaw and New Zealand ship broker and valuer James Lewis giving evidence, Radio New Zealand International reports.
The commission's assistant lawyer says witnesses to be called in the next few weeks include Prime Minister Feleti Sevele, who was served with a summons on Wednesday to appear on 12 February.
Others to give evidence include the Minister of Finance, the Chief Secretary to Cabinet, the former Minister of Transportation, the chief executive officer of transportation and the Treasury department.
The inquiry adjourns for one week from 29 January.