Tongan Prime Minister is expected to appear before the inquiry into the sinking of the ferry Princess Ashika on Thursday.
A Royal Commission in Nuku'alofa is investigating the August disaster which cost 74 people their lives.
Prime Minister Felete Sevele is expected to follow further evidence by finance minister Oteni Afualo Matoto.
On Wednesday, the minister told the inquiry the then-transport minister described the Princess Ashika in glowing terms as a good buy.
Mr Matoto said the government was under huge pressure to buy the ferry because the ship then in use, the Olovaha, was barely seaworthy.