Single-person ambulance call-outs will end in the next four years but a union representing the staff say the move is still not enough.
Health Minister Jonathan Coleman says a $59.2 million boost will be delivered over four years to eliminate single crewing.
It means call-outs normally attended by two ambulances will now be attended by one, consisting of at least one trained paramedic and an extra person who may be an "emergency medical assistant".
St John, which runs ambulance services everywhere except Wellington, said the extra money would allow it to boost its paid ambulance staff by 420, or more than a third, from 1168 to 1588, plus an extra 10 staff in the Auckland control centre.
The biggest increases will be in rural areas, where many call-outs are currently single-crewed.
St John's central-west region, including the Waikato and Taranaki, will get 78 extra staff, followed by 69 in the central-south (Whanganui/Manawatu/Hawke's Bay), 65 in the central east (Bay of Plenty/Gisborne), 55 in Auckland (including control centre), 46 in Northland, 44 in Canterbury, 41 in Nelson/Marlborough/West Coast and 32 in Otago/Southland.
"Ending single-crewing is one of the most significant developments in our ambulance service history," St John chief executive Peter Bradley said.
"We will be able to recruit 430 frontline jobs over four years and provide rural New Zealand with the same crewing levels as urban areas; a move that will save more lives and make it safer for our crews."
Central-west operations manager Stuart Cockburn said the move would make a huge difference not just for patients but also for ambulance officers' safety.
"I have been in fear of my safety before," Cockburn said.
"I was responding to a cardiac event at a gang house. I was by myself doing CPR and trying to do everything I could. I had gang members standing there behind me saying, 'If your patient dies, you die.'
"To have someone with me would make the job a heck of a lot easier and safer."
However Ambulance Professionals First, a branch of First Union representing more than 1000 paramedics, said about 300 of the new jobs would be for "emergency medical assistants" without adequate training.
"Emergency medical assistants will receive just three weeks training and won't have the authority to practise without supervision," said spokeswoman Lynette Blacklaws.
"In metropolitan areas ambulances are crewed with two qualified ambulance officers. This means they can care for multiple patients at a single incident, they can consult with each other and they have the benefit of a second opinion when making critical medical decisions in crisis situations," said Blacklaws.
"We want to see that level of service right across the country, not just in the major population centres."
A St John spokeswoman said the extra staff would include "emergency medical assistants (EMAs), emergency medical technicians, paramedics, intensive care paramedics and clinical control centre staff".
"We don't know exactly how many of those new positions will be EMAs. We have just had the announcement and will work with communities and staff to determine what the right mix for each community is," she said.
"Emergency medical assistants will undergo a minimum five-month training programme, starting with foundation ambulance education and culminating with EMA focused training."
Coleman said $31.2m of the extra funding over four years would come from taxpayers via the health vote. The other $28 million will come from the Accident Compensation Corporation (ACC).
ACC will also pay $192m in the next five years towards the recent $2 billion plan to raise caregivers' wages in aged care and disability services. Coleman said then that the pay deal could affect ACC levies.
"ACC levies are set for the coming years, but may possibly increase over the next decade to support this," he said last month.
St John said the changes would increase total state funding through Health and ACC from $139m in 2015-16 to $161.6m in 2017-18, raising state funding from 69 per cent to 74 per cent of ambulance costs.
The other $55.7m (26 per cent of total costs) will still have to be raised through fundraising and fees charged to ambulance patients.