Dozens of meat workers have defied the orders of their Affco bosses and taken the first-ever observed Waitangi Day off work despite threats of disciplinary action.
Affco, the country's fourth-largest meat processor, sent a letter to staff at its Rangiuru meat plant on Friday informing them that a refusal to work on Monday could amount to an unlawful strike.
Not turning up could also amount to serious misconduct, and the workers and union could be sued for damages, the letter states.
However, all but two of the 35 staff covered by the old NZ Meat Workers Union agreement decided to flout the order and stay at home, said union organiser Darien Fenton.
"They wanted to join with the rest of the country and enjoy the first-ever Waitangi Day observed on a Monday, but they know there will be vicious consequences for them tomorrow," she said.
"There's a lot of anger and confusion, and of course, worry."
A further 60 staff have gone to work at the plant today as required under their non-union agreement.
Ms Fenton said the union had contacted the company over the letter but had received a brief reply restating the firm's beliefs that Saturday was a public holiday and Monday was not.
A call to Affco head office in Horotiu was met with an voicemail recording which states: "You've reached us on a public holiday so our staff are not in the office".
The union said the Affco letter had left a sour taste in the mouth for the company's many Maori employees, and had also had let down other employers who have worked hard to comply with the new rules.
Under law changes agreed by parliament in 2013, where Waitangi Day falls on a Saturday, the holiday is observed on a Monday for workers who do not normally work weekends.
Waitangi Day marks the signing of the Treaty of Waitangi between the Crown and various Maori chiefs from the North Island.