It is being claimed that the vessel, the Princess Ashika, which sank off Tonga with the loss of more than 90 lives, was dangerously rusty and had to have water pumped out of it continuously before it even left the wharf.
With 149-people on board, the ship sank north west of Nuku'alofa last Wednesday.
Only two bodies have been recovered and 93-people remain missing after the tragedy.
The owners of the first vessel to reach survivors says the ferry was in a debilitated state and shouldn't have been at sea.
The MV Pulupaki responded to Wednesday's distress call and plucked survivors from life rafts, about 86-kilometres north west of Nuku'alofa in Tonga.
Tu'i Uata says the ferry sinking in the space of a minute leads him to believe its integrity was compromised, and was far from intact.
He says the Princess Ashika had been berthed besides his own ship, and the entire day before the ferry left he saw water being pumped out.
Mr Uata also says he saw a hammer go through the hull during rust repairs when the ferry first arrived in Tonga, after a troubled journey from Fiji.
The New Zealand and Australian navies have suspended their search for the wreck until at least tomorrow night because of bad weather.