Twenty-nine people could lose their jobs in Christchurch at Tasman Insulation, the company which makes Pink Batts.
The firm wants to close the Christchurch plant entirely and make its Auckland plant operate "24/7". The company says the cuts are the "best way" to retain an NZ Pink Batts plant.
The proposed cuts are a result of stiff competition from oveseas manufacturers, according to the Engineering, Printing and Manufacturing Union (EPMU).
"This is yet another company who are saying they cannot compete with cheap overseas imports in the current economy," says Ron Angel, EPMU organiser for construction.
"Tasman are saying they're committed to keeping Pink Batts New Zealand-made, but we have no guarantees they'll be able to do that unless the dollar comes down and our manufacturing industry gets some support from the government."
The company is proposing to consolidate its manufacturing operations in Auckland, creating nine new jobs in its Penrose facility.