Cereal maker Sanitarium has indefinitely suspended Weet-Bix manufacturing operations at its Christchurch factory as a result of damage the facility sustained in the February 22 earthquake.
General manager Pierre van Heerden said 36 staff at the plant had been offered redundancies as the result of the closure.
More than 60 staff were sent home on full pay late last year when manufacturing was suspended, and since then the company has been running its Auckland plant overtime to supply the South Island with Weet-Bix.
The firm said the decision to indefinitely halt operations was made after the company received an engineering report on the buildings last week.
"After numerous discussions with our engineers, insurers and Cera, it has become clear that as a result of the February 2011 earthquake the tower block [used to make Weet-Bix] has been damaged to an extent that it puts staff safety at risk," van Heerden said.
The company said that as well as redundancy packages, affected staff had been offered a support programme to assist them "through the transition ahead".
Staff had been given the opportunity to apply for roles in Sanitarium's Auckland facility and positions at its sister firm in Australia, van Heerden said.
Sanitarium said its intention was to get Marmite production at the Christchurch plant up-and-running as soon as possible, and the site would continue to function as a distribution centre.
It would be at least 18 to 24 months before the company could manufacture Weet-Bix at the Christchurch site, van Heerden said.
In the meantime, he said the company would continue to transport Weet-Bix to the South Island from Auckland, as well as Sanitarium factories in Australia.
Van Heerden said that although staff had been expecting the news of the closure, it still came as a shock.
"They've had severe issues in their personal lives [as a result of the quakes] and then they get this at work," he said.
"The majority" of the 36 staff offered redundancy packages were expected to take the offer up, he said.
Van Heerden said no decision had been made on the long-term future of Weet-Bix manufacturing in Christchurch.