Winstone Plastics had previously operated in Porirua under the name Novoplast Ltd when the decision was made to transfer operations to Palmerston North. These new premises were opened by the Prime Minister R D Muldoon. Winstone Plastics employed 135 people and the factory and office complex covered 8,000 square metres on a 6 acre site. They manufactured PVC roof panels, pipes, plumbing and land drainage materials. Also operating within the factory was the moulding operation of Novakey (NZ) Ltd a joint venture between Winstones and Reed Building Products Ltd of Australia producing a range of PVC fillings for the plumbing trade.