Retail organiser Marleina Kerapa says workers have tried multiple times to communicate pay concerns to their employer.
"The union has had multiple bargaining sessions and attended mediation with the employer but the offer is still significantly less than what other Pak'nSave employers are offering," Kerapa said in a statement.
"The minimum wage shouldn't be what a majority of workers are on, that's not what it's for.
"It's a minimum, not a target for all."
She said workers were struggling to make ends meet on the wages they were being paid.
"This is about the fact that workers cannot survive on the wages paid at Pak'nSave Whakatane," she said.
"These workers have families to feed and have been loyal to their employer over the years. It's time they got a fair share of his profits."
Asked for the comment on the strike action, Pak'nSave Whakatane owner-operator Andrew Soutar said negotiations with First Union had been ongoing for some time.
"We believed we were making great progress with our third and latest offer," he said.
"Sadly, this has not been accepted by the union which has now notified us of industrial action. We do not think this is the best way forward or in the interests of our team, as we had made a competitive offer which meets the market."
Souter said he was open to continuing the conversation with staff and their union representatives.
