The troubled Aratere will be inspected for rats again tomorrow after it returned from Singapore in September carrying the vermin.
A Regional Public Health spokeswoman said all standard biosecurity processes were carried out on the Aratere's arrival to New Zealand.
Interislander staff immediately addressed the pest issue by hiring an exterminator once identified and there were no public health concerns.
But as a precaution the ship would be inspected again tomorrow, she said.
KiwiRail chief executive Jim Quinn confirmed that, among other problems with the ship, rats had been found after it left Sembawang Shipyards in Singapore. "Were there some? Yes there were. Did we fix it? Yes we did." Traps and poison had been laid, he said.
"A pest company was used again when the ship arrived back in New Zealand to make sure the issue was dealt with in full. We advised MAF of this, obviously we've got responsibilities around that.''
A crew member told The Dominion Post the ferry had been over- run. "There was rats in the engine room, in the ceiling, all over the place . . . There was even a rat in the ship's bar," the crew member said.
"Now they've got into the deck head, the actual ceiling, and they are chewing through the fibre-optic cable and doing all sorts of damage. All they need to do is chew through the cables between the bridge and the engine room and you'd be in serious trouble.''
There was even a rat in the ship's bar, the crew member said.
"It's a bit of a joke 'cos they can't catch it.''
However, Mr Quinn said there was no evidence the rats had chewed through any sensitive cables or caused damage.
It was not believed there were any more rats on the ship but traps were still being laid to make sure.
"We feel that the crew don't need pets.''
A Health Ministry spokesman said Wellington's Regional Public Health was working with KiwiRail to solve the rat problem.
"They issue ship sanitation certificates and make sure [Kiwirail] do what they need to do to keep the problem under control.''
MAF Biosecurity was acting in an advisory role, a spokeswoman there said.
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- The Dominion Post
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