"Nurses and rest home workers are among some of the poorest paid workers in New Zealand," Ms Roche said.
"These workers do the job because they are passionate about caring for the residents and believe the work they do makes a difference."
Service and Food Workers Union spokesman Alastair Duncan said he hoped the strike would have a "minimal impact" on care.
"In fact, we know that in a number of the sites, residents will be joining the workers on the picket line," he told Radio New Zealand this morning.
"This is a symbolic action. This is the staff saying to a corporate company, 'You need to listen to us, this is the last straw of frustration'."
Staff would still be available if there was an emergency.
"But we also have given extended notice of the strike and we expect the company to have covered fully."
Negotiations have been ongoing since last June, and longer extended action could follow next week.
The eight months of negotiations had been frustrating, and the 3.5 per cent the unions were asking for was less than the rate of inflation, Mr Duncan said.
Other providers had passed onto their workers an increase in Government funding but Oceania had not, he said.
Retirement care was a growth industry that needed 30,000 more workers in the future but the sector was underfunded, said Mr Duncan.