Workers in rest homes owned by the Radius group have voted to take strike action over a pay dispute.
About 900 workers from about 20 facilities across the country held stopwork meetings on Wednesday after six months of failed negotiations with their employer.
A spokesperson for both the Service and Food Workers Union and the Nurses Organisation, Chrissy Darth, says Radius has not passed on to its staff a 1.73% increase in funding from district health boards in 2010.
Ms Darth says the decision to strike was not an easy one for union members and it is an absolute last resort.
"Pulling strike action is never easy for caregivers - these people are caregivers by nature and for them to make this decision, it's huge, it's massive."
Managing director of Radius Residential Care Brien Cree says the extra funding from the DHBs was to cover the cost of a government-imposed auditing regime and was not intended for staff.
He says 40% of Radius rest home workers are not union members so the care of residents will not be compromised by a strike.