"People were vebally abused, a customer was assaulted and families were crying," she said. "We were very disappointed by how agressive things turned.
"This is not what you expect when you go shopping in New Zealand on a Saturday morning. Some of our staff were in tears and some asked to go home."
Police arrived after 20 minutes and more than 50 chanting protesters outside dispersed.
Kate Davis, a First Union organiser, was one of those in the human chain.
She said the action symbolised that Bunnings workers were being effectively chained to their workplace through a new roster proposed by management.
"People are being chained by inflexible hours," she said. "We need to keep up the pressure and let people know this unacceptable."
Another chained protester, Glen Eden resident Rhi Thomson, said she was showing solidarity with Bunnings workers.
"I used to shop here but I won't be doing so again until Bunnings start showing their employees some respect."
Bunnings shopper Tony Bircham, from Te Atatu, was inside the store when the chaos erupted.
"It's inconvenient but workers have the right to protest," he said. "They clearly have a grievance and this has made me think twice about shopping here."
Bunnings' marketing manager Valerie Stanley had earlier declined to comment about the protest in New Lynn and referred media to a statement released by the company last night.
That statement said Bunnings had offered staff a minimum $17.50 hourly pay rate and team members would receive an "absolute minimum" pay increase of 4 per cent this year, with a further guaranteed minimum of 2 per cent next year.
"Bunnings is committed to supporting the needs of our valued team and providing a healthy work/life balance," the statement read.
"Bunnings can confirm that it will not make wholesale change to our teams' roster patterns, however some changes may occur when required. Any and all changes will take place in full consultation with the team member, with at least four weeks advance notice given, so that any significant commitments, such as family responsibilities, can be raised and taken into account.
"Team members normally receive notice of their proposed rosters six weeks in advance."