Industrial action at AFFCO's meat works has escalated.
The company has locked out a further 213 workers at its Rangiuru site near Te Puke from Tuesday, bringing the total number of locked-out workers to nearly 1,000.
Some 700 union members are on a 24-hour strike on Tuesday striking in response to that.
The industrial action began last week, when AFFCO locked out more than 760 workers at five of its eight plants after negotiations over a new collective agreement broke down.
AFFCO wants more flexibility in its hiring practices.
Rangiuru workers joined a full union strike held on Friday in response to the lockout, and are in turn locked out from Tuesday.
The company's operations manager, Rowan Ogg, says AFFCO's plants are still operating using workers on individual contracts.
The Meat Workers Union says workers would be picketing outside the plants again on Tuesday, but that they want to get back to negotiations this week.
General secretary Dave Eastlake told Morning Report that production is at a low level and he suspects the company would normally have laid off people at this time of year, but has chosen to lock out workers and "put a bit of heat" into the dispute.
"We're certainly determined that we're not going to give away conditions that have been in place just because there's a lack of production around."
Two of AFFCO's plants, at Napier and at Wiri in Auckland, are unaffected by the lockout.
The company says there is no timeline for settling the dispute.