The New Zealand shipping agent for 10 men who jumped ship in Port Nelson says they were not mistreated while aboard the vessel.
The Department of Labour says the men from the Korean fishing boat have said they left the ship because of employment conditions and mistreatment.
The International Transport Workers Federation also said the men could have been driven to desertion by inhumane conditions.
The men handed themselves into police on Thursday afternoon and are being questioned by Department of Labour inspectors.
The federation says there is no protection for foreign workers in the fishing industry who face long hours with little pay.
But Peter Dawson, the lawyer for the shipping agent Dalgan Kim, says both he and the agent have visited the ship and there was no evidence that conditions on it were poor.
Dawson says the men have been paid and his client thinks they deserted the ship because they wanted to get jobs in New Zealand.
The Department of Labour says an officer is being sent to inspect the ship to add further information to the investigation.
