Ballance Agri-Nutrients blames urban sprawl for the closure of a fertiliser plant at Whangarei, with the loss of 25 jobs.
The company says the site will remain open as a service and distribution centre only. The company is moving production to Tauranga.
General manager Greg Delaney said demand for super-phosphate produced at the plant has been falling steadily over the past 10 years, because a lot of farmland in Auckland and Northland has been converted into lifestyle blocks.
Mr Delaney said Ballance is offering jobs elsewhere in the company to staff affected by the closure and it hopes to keep forced redundancies to a minimum.
