More than 20 staff have laid formal complaints against a single store manager at a branch of The Warehouse, saying they feel bullied and demeaned.
At least one worker said she was so stressed she needed counselling before she eventually resigned from the store, where the manager still works.
Staff report being yelled at in the middle of the store, picked on because of their age, ignored, given impossible workloads, and having their shelf-stacking mistakes photographed and kept on file.
In an email to First Union, the company's initial response to the complaints from 22 current and former employees of the branch, made in May, was that it was an issue of "management style" rather than bullying.
The Warehouse has since carried out an internal investigation into the complaints and said "lawful and appropriate steps have been taken and [the matter] is now resolved".
The company did not say whether it had found evidence of bullying, or what the "lawful and appropriate steps" it had taken were.
First Union said The Warehouse had now offered to show union representatives the investigation report, after RNZ contacted the company.
MBIE's website describes workplace bullying as "repeated unreasonable behaviour that makes someone feel picked on, humiliated, threatened, offended or upset".
It could include giving someone the silent treatment, setting impossible deadlines or giving staff belittling tasks that are not in their job description.
One complainant, who had worked at the branch for 16 years, said there had been no tension between management and staff prior to the current manager's arrival.
"Up until then it was a fabulous store to work in. We all worked as one team, it was absolutely awesome…Everyone just got on and did their jobs."
The complainants are older workers - the youngest are in their forties and some are close to retirement age - and said they felt they were targeted because of their age.
"When he came to have his first meeting with [the night shift]... he looked at us and said he believed that the future of the store was with the young," one worker said. "Looking at us, the majority of us were not young."
The workers said they began to be constantly reprimanded for minor, "picky" mistakes, sometimes in front of other staff or customers.
Two staff members told RNZ they were shown photos the manager kept on file of mistakes he said they had made while re-stocking shelves.
'People began to distrust each other'
One of those workers, who was abruptly shifted into a department he had no training in, said he was called to the manager's office on a weekly basis, after working at The Warehouse for eight years with no previous complaints about his work.
"I was going though it for nearly 12 months, heading up into his office trying to explain myself," the man said.
Among the complaints RNZ has seen, many staff spoke of being assigned impossible workloads each shift.
"A task list is what they want you to do in eight-odd hours," one man said. "I would see this task list and think, I can't do this, it's way too much. Even my immediate supervisor would look at it and say, I don't know how you're going to do that."
Other staff said they felt spied on and monitored.
"If we were ever seen talking…next thing you'd know [an assistant manager] would be at the end of the aisle saying, what are you doing?" one woman said.
"People began to distrust each other because they didn't know where he was finding things out from."
The same woman said she was yelled at in the middle of the store after a dispute about a single day of leave came to a head.
The woman had taken Christmas Eve off to spend with her family, after her direct supervisor told her it had been approved, she said.
After she returned to work, the store manager disputed the leave had ever been approved, prompting a months-long disagreement.
Eventually, the manager asked her to come to his office for a meeting, without union representation, which she refused to do.
"This conversation went on for about half an hour…This was with other staff around," the woman told RNZ.
"He [eventually] turned around, really angry, and he said, 'You'll regret this'...He walked down towards the back of the store still yelling and waving his finger at me, 'You'll be sorry - you'll look back on this and you'll be sorry.' I'd lost all the saliva in my mouth with fear."
Among the 22 complainants are four former workers, who said they left because they felt bullied.
"Before I left I was in counselling because of the stress," one woman said.
"I'd just had enough. Every night going in I was getting harassed by him."
Another woman, who is still employed at the store, said she "loathe" working there.
"I could leave tomorrow but I'm not going to, not while that man's in charge - I want to see him gone."
'I thought they would take us seriously'
First Union organiser Jane Marti said the situation at the store had got "progressively worse" in the two years she had represented the workers.
"The indicator of that for me was how much time I spent at that store compared to my other 50 sites."
The workers decided to lay formal complaints about four months ago, Ms Marti said.
"There came a tipping point where everyone got on board and realised that it wasn't just [one person's] issue, it was a storewide issue."
Workers at the manager's former branch had also made complaints in the past but nothing had come of them, she said.
"The regional manager is aware there are issues."
In a written statement, The Warehouse said it had taken the allegations "very seriously and a thorough investigation was conducted and concluded".
The company said it could not discuss individuals or specifics, because it was an employment issue and subject to the Privacy Act.
It was "not aware of on any ongoing concerns".
"The Warehouse is confident that its people are managed fairly and appropriately and all store management teams are given ongoing training and support to lead customer focused, high performing teams," the statement said.
The company took aim at First Union, saying the union's decision to talk to RNZ about the issue was "deeply concerning and reflects a disregard of good faith".
One worker said she was upset that the manager was still working at the store.
"I thought they [The Warehouse] would take us seriously, I thought they would go by their own standards that they do not tolerate bullying and they do look after their staff."