Shoppers walked past picket lines while picking up their groceries on Saturday as union members demonstrated outside Rotorua Pak'nSave.
The protest came after members of First Union endorsed industrial action against what they allege to be a "campaign of bullying and intimidation" by bosses - claims which the supermarket has strongly denied.
One held a large banner reading "Pak'nSlave" in the supermarket's signature black font and yellow logo while a giant inflatable rat loomed over the protestors. Protestors handed out leaflets to passing cars and pedestrians.
Speaking to the Rotorua Daily Post at the protest, senior First Union organiser Bill Bradford claimed that store management been "bullying staff for a long time".
Neither the Rotorua store owner or Antoinette Laird, Corporate PR Director, Foodstuffs NZ could be contacted for comment over the weekend. However on Friday Ms Laird told the Rotorua Daily Post the company was in the very early stages of talks with First Union regarding contract negotiations for staff.
She said Foodstuffs refuted all allegations made by the union and was disappointed by the demonstration as it believed there were "more constructive" ways to reach resolution.
"As a business we are happy to facilitate the Union negotiation process, and are keen to work towards discussing an outcome that is appropriate for all concerned."
Mr Bradford estimated the overall turnout for yesterday's demonstration to be around 90.
During the demonstration guards in high-vis jackets patrolled the car park, and a number of Armorguard vehicles stood parked outside the entrance.
Despite regular honks from passing cars, not everyone was 100 per cent behind the protest.
One shopper said she couldn't fully sympathise with the workers' concerns.
"There are probably workers who do deserve a pay rise, but I don't think they work any harder than a lot of others, for example the cleaners at the hospital. Their jobs aren't that hard," she said.
A duty manager working at the store said the day had been "hard, but we did our best and got through it".