The National Ambulance Sector Office (NASO) has issued a request for air ambulance services proposals. It does not include Rotorua or Taupo, which are the bases for the BayTrust and Greenlea rescue helicopters respectively.
The list of regions where air ambulances would be based under the new system would come into effect on November 1.
Philips Search and Rescue Trust operates rescue helicopters and air ambulance services from bases in Hamilton, Tauranga, Rotorua, Taupo and Palmerston North.
In a media release the trust said it would respond to the request for proposal asking that Taupo be re-included.
"We think that an improved service located from Tauranga and Taupo ought to be able to cover the responsibilities currently carried out by the Rotorua service, in an appropriate way," the statement said.
"Discontinuing both Rotorua and Taupo, will see a significant degradation in the public's access to pre-hospital emergency helicopter care."
It said the Tauranga and Taupo services virtually entirely overlapped the area covered by the Rotorua service.
The Greenlea Rescue Helicopter was dispatched for four jobs in two days this week, said a second media release.
The first was a maternity transfer to Waikato Hospital which, according to the trust, would have been delayed by at least 40 minutes if the helicopter was removed from service.
A second, involving transport of a stroke patient from Turangi to Rotorua, would have been delayed at least 45 minutes, it said.
A change.org petition to keep Taupo's service has gathered more than 5600 signature in two days.
The Tuwharetoa Maori Trust Board is also calling for the Taupo rescue helicopter service to continue.
Board chief executive Topia Rameka said the prospect of losing it was concerning.
"We understand that under the new system Taupo would still be serviced by other areas, but they are a further hour away – which could be the difference between life and death for the hundreds of rescues made in our rohe [region] every year."
Local MPs have also spoken out about the proposal.
Rotorua-based list MP for NZ First, Fletcher Tabuteau, said rescue helicopter services were under "incredible hardship" and had been for some time.
"There is clearly a need for all responsible parties to collaborate and communicate to ensure that a fully resourced and responsive rescue helicopter service is available," Tabuteau said in a written statement.
Waiariki MP Tamati Coffey told the Rotorua Daily Post a review into the fleets across New Zealand was a good thing.
"I'm into making sure we've got the best possible service. But I want to get to the bottom of the facts," he said.
"We need to make sure we've got really good representation here."
Coffey said he would be disappointed to see the loss of the Taupo service in particular, because it serviced the Tongariro Crossing and ski fields.
National's Rotorua and Taupo MPs Todd McClay and Louise Upton expressed concerns about the proposal.
"It is unacceptable that this essential service is at risk of being moved away from this region. The Rotorua and Taupo helicopters have helped to save hundreds and hundreds of lives and are an important part of a timely rescue response service for our region," McClay said.
The request for proposal requires the seven North Island providers to be distilled to two regions; Auckland/Northland, and the rest of the North Island.
Within the second area it proposes the locations for helicopter bases would be Hamilton, Tauranga, Gisborne, Hawke's Bay, Wellington, Palmerston North and New Plymouth.
There would be a shift from the current mixture of twin and single engine helicopters to solely twin engine aircraft and also a significant ramping up in the requirements of crewing, the trust said.