"We now get paid less than our DHB colleagues, even though we are all registered nurses.
"Despite our patience, nothing has happened. Negotiations have been going on for a year and nothing has brought us to parity."
Miller said there was a pay offer from the Government, but it didn't meet their requirements.
"There was a pay offer, but it didn't address the pay parity. We just want to be paid the same as registered nurses in the DHBs."
Union organiser Gail Ridgway said more than 70 nurses in the Whanganui area stopped working. There was a mediation on Tuesday as a last chance to resolve the issue.
"That was the last-ditch effort, and that was obviously unsuccessful. These guys are all in their specialty fields as well."
There were major rallies in Christchurch and Wellington, as well as a number of other smaller ones around the country.
"It's not against the employers, it's about the funding from the Government," Ridgway said.
"Most employers are very supportive, they just don't have enough money.
"We've never caught up. Aged care are even lower than these guys and they are still nurses."
Shannell Eparaima said if PHC nurses don't get pay parity, patient charges may have to increase so employers can bring up their wages.
"[Patients] are already playing a lot. The health of our community is actually suffering because of what they have to pay already.
"We don't want to put the prices up."
Earlier this week Minister of Health Chris Hipkins said he was not going to get involved in industrial negotiations.
"Ultimately they are employed by private practices, the Government is not their employer and so there are a variety of factors that those employers take into account in their negotiations.
"In general, the Government supports pay parity. Equal pay for equal work, that's the basic premise that we do support. Having said that, in primary care we are not the employer of those nurses."