Meat processing company AFFCO has locked out hundreds of employees in a dispute about a new employment contract.
The company issued the indefinite lockout notice for 762 unionised employees after mediation broke down on Tuesday.
AFFCO is offering a 4.3% pay rise over two years, but only if a new collective agreement is signed without dispute and is adhered to.
The New Zealand Meat Workers Union national secretary Dave Eastlake says the company is trying to starve members into allowing it complete flexibility in terms of their employment.
He says the union has done its utmost to prevent the lockout by answering most of the company's concerns.
"They sort of give us the impression that they probably don't want a collective agreement and perhaps they have some other agenda that so far they haven't disclosed to us."
The union says the contract would give the company the right to reduce workers' pay without agreement.
AFFCO chief executive Hamish Simson says that is not the case and the company just wants the right to operate its plants as efficiently as it can.
"We have offered a pay increase and, under our claims, we have also stated we are protecting the daily pay of our employees when we make changes."
Mr Simson says the company is seeking changes on manning and chain speeds - the rate at which a plant processes meat.
He told Morning Report the company wants long-running legal action over the collective contract to end and for such issues to be resolved in mediation.
However Mr Eastlake told the programme that court action has been required to get the correct legal interpretation of the collective agreement where the company has misinterpreted it.
Lockout affects five plants
The lockout affects staff at five of the company's eight plants; at Moerewa, Horotiu, Imlay, Wairoa and Manawatu.
Laurie Nankivell has worked at the Moerewa plant for 35 years and says the last industrial action he can remember was a strike in 1985.
He says many people in the area work at the plant and the whole community will feel the affects of the lockout.
The meat processing company says there is a possibility it may extend a lockout to include all 2300 union members on its staff.
The Meat Worker's union, meanwhile, says union members who have not been locked out plan to strike on Friday morning for 24 hours.
Wairoa mayor Les Probert told Morning Report that AFFCO brings hundreds of thousand dollars every week into the town, some of which is spent locally, so the industrial action will hit the town hard.