Affco meat company is locking out more than 700 meat workers following an ongoing employment dispute.

The company has given notice of the indefinite lockout of workers at five of its plants across New Zealand from Wednesday, Meat Workers Union secretary Dave Eastlake said on Saturday.

Affco wants workers to accept major changes to a collective employment agreement, giving the company total employment flexibility, he said.

"Our members will be shocked that this company, now wholly owned by the Talley family, has taken such a cruel and unnecessary step in order to get exactly what it wants in their employment agreement."

The workers would meet to discuss the lockout and were calling on Affco to withdraw the lockout notice and return to the bargaining table, Mr Eastlake said.

"The lockout demands of the company are very similar to those being demanded of the workers at the Port of Auckland and reflect a new determination by some employers to screw down working conditions to the absolute bottom in this country - the low road of employment relations."

The lockout notice, affecting 762 workers, follows an 18 month dispute over the collective employment agreement, with two parties negotiating a new agreement during the past three months, TVNZ reported.