The maker of the well-known Klip It kitchen containers, Sistema, has been sold to an American company.
The company has been bought by New Jersey-based Fortune 500 company Newell Brands for $660 million.
Sistema was founded by its managing director Brendan Lindsay in the mid-1980s in Hamilton and has since grown into a company with more than 700 workers and sales in more than 90 countries.
Mr Lindsay said Newell Brands has the expertise, market access and resources to help Sistema expand, particularly in North America, but he only sold on condition it kept manufacturing in New Zealand.
"I am absolutely thrilled that Newell has agreed to keep manufacturing in New Zealand for the next 20 years at our recently opened 52,000sqm manufacturing facility at a greenfields site near Auckland Airport."
Newell Brands president Mark Tarchetti said they had been looking at Sistema for some time and had made several attempts to buy what they regarded as a world-leading brand.
"We believe there are some very exciting opportunities for the company and we plan to leverage our position as a Fortune 500 company to provide the platform for further growth for Sistema."
Newell has a market value of more than $22 billion, and owns a wide range of consumer goods businesses covering household products, tools, baby goods, and its brands include Papermate, Sunbeam, and Dymo. Sales in the current year are expected to top $US16bn in 125 countries.
Earlier this year, the E Tu union accused Sistema of being a "sweatshop", with migrant process-workers required to work five 12-hour shifts - a 60-hour week - for the minimum wage.
The company said the factory operated around the clock and staff were able to work shifts that best suited them and Sistema.
The union's industry coordinator, Anita Rosentreter, was optimistic conditions would improve for workers after the sale.
"The fact that they're majorly migrant workers means that they often find it difficult to speak up for themselves. We see this as an important opportunity to better establish some decent working rights and hopefully lift their pay," she said.