Dozens of Pak'nSave workers in Hastings are picketing on Saturday in a bid for better pay.
About 40 staff will be handing out flyers and speaking to customers about their employment woes.
First Union organiser Mike McNab says it's the final push.
"The union is always prepared to bargain and negotiate with the employer. To take this picket is an extreme action and we really didn't want to do this."
The supermarket has responded saying it is above market with its employment terms. Mr McNab disagrees.
"Workers are paid poverty wages, and well below the Living Wage - the owner seems to want to be a minimum wage employer."
The new Living Wage equates to a yearly pay of $42,744. The minimum wage is about $34,320.