But the heavy rain and dangerous high wind forecast in Canterbury mean demonstrations have had to be cancelled.
The vast majority of the country's children would not be at school because of the primary and secondary teachers' strike.
The next biggest impact was in the health sector, where allied health workers such as physiotherapists and psychologists, as well as nurses who were part of the PSA union, were off for 24 hours.
Senior doctors and nurses from the bigger NZNO union would be off for four hours, from 11am to 3pm.
About 1200 ACC workers were striking for 14 hours, with firefighters stopping for one hour.
Health NZ said it expected thousands of appointments and procedures would have to be postponed, but it stressed hospitals, emergency departments, mental health unit and some other services would still be open.
People should turn up for their appointments unless they had been told not to, it said.
Auckland police warned there would likely be big disruptions in the city centre because of a rally down Queens Street from Aotea Square.
The march was set to start at 1pm but workers would gather about an hour before that.
It was now the single biggest protest because the other main rally in Wellington - to Parliament - had to be cancelled because of the red-category wind forecast.
Rallies were also called off by weather in Christchurch, the rest of Canterbury, Blenheim, Wairarapa and parts of Central Otago.
Many were still going ahead in other areas of the country, but some on the West Coast and Invercargill were moving indoors.
Three government ministers made last minute calls on Wednesday for the strikes to be called off.
In a joint statement Judith Collins, Simeon Brown and Erica Stanford said the action was unfair and unnecessary.
Collins, the Public Service Minister, said the strike would not help anyone.
"It is a stunt targeting the government but the people paying the price are the thousands of patients who have had appointments and surgeries cancelled, and the hundreds of thousands of kids who will miss another day at school," she said.
But PSA national secretary Fleur Fitzsimons said the ministers were out of touch with the pressures on the health system and the impact of the rising cost of living on workers.
"Health workers are standing up not just for themselves, but for the patients who deserve staffing levels that can provide the safe, quality care they deserve," she said.
The union estimated about 100,000 workers were striking.
