About 100 Fletcher Building workers from Waikato to Northland are going on strike this morning in frustration at stalled pay negotiations.
First Union issued strike notices to the company overnight to let it know workers at Firth Concrete, Laminex, Mico Bathrooms and Winstone Aggregates would not be returning after the long weekend.
First Union secretary for manufacturing Jared Abbott said the workers had not been given a fair pay rise and negotiations with the parent company had come to a halt.
"Essentially the workers are quite frustrated, some have been negotiating since February, quite a few since May, and they've got to the point where they want to send a message to the company to get back to the table and resolve some of the outstanding issues."
Mr Abbott said he expected workers would picket the company headquarters in Auckland this morning.
Fletcher Building said it highly valued its nearly 10,000 employees and was expecting fewer than 45 people from three of its businesses to strike.
New Zealand's biggest building company, Fletcher Building reported in August that its net profits had fallen 80 percent in the year to June, to $94 million down from $462m the year before.