The Ministry for Primary Industries says it's introduced new measures against stink bugs.

The Ministry says all used vehicles will now undergo inspection and cleaning at an MPI-approved facility in Japan prior to export.

This announcement comes as tens of thousands of jobs in the car retailing industry are at risk as a number of ships float aimlessly in the Pacific.

The car carriers have been turned away from New Zealand ports after hundreds of marmorated stink bugs were found on board.

Businesses linked to the car import industry are standing down employees as biosecurity concerns prevent thousands of cars from entering the country.

Four ships from Japan have been found to contain stink bugs - a noxious pest which could destroy our fruit and vegetable industry.

The ships have been barred from unloading at the Ports of Auckland until they undergo fumigation.

The first ship was turned away two weeks ago.

David Vinsen from the Imported Motor Vehicle Industry Association says some businesses have been hit hard.

He says some vehicle compliance businesses have asked staff to use their leave, while some have been asked to work as little as one day a week due to a lack of work.

Mr Vinsen says up to 12,000 cars are on board the ships, while backlog of around 11,000 new and used vehicles has built up in Japan.