"These are incidents where NZFS could make a difference," the report stated. "In the example above, we could wait until the child becomes unconscious and unresponsive before responding or we can choose to initiate a response early to save time."
It's not clear if the patients listed as examples survived.
Fire bosses yesterday said firefighters attended all medical emergencies where possible, but the union said further investigation was required about the workings of a Memorandum of Understanding between Fire and Emergency NZ (FENZ) and St John Ambulance which is based on a colour-coded patient triage system.
Under the agreement, fire centres must dispatch the closest available staff for "immediately life-threatening (cardiac/respiratory arrest)" purple calls.
However only highly-trained first responders are supposed to go to red calls, which are "immediately life-threatening or time critical".
First responders are firefighters trained to a higher level of first aid and can deal with emergencies without assistance. Staff without this training, known as co-responders, provide life-saving treatment in conjunction with paramedics and only attend purple calls.
The choking child and potential heart attack incidents were categorised red calls by ambulance 111 call centre staff, and were in areas where FENZ did not have first response units. In both cases the responding ambulances were farther away than available co-responders but the firefighters were not sent.
FENZ national operations manager Paul Turner said if St John confirmed a co-response would help the patient, then "Fire will send a co-response unit, if available".
He said this response existed in protocol in the communication centre which allowed them to work on a case-by-case basis.
"We believe the Memorandum of Understanding is working well to protect New Zealand communities and save lives."
Of 26,000 emergency call incidents since January 1 last year to June this year, released to the Weekend Herald under the Official Information Act, 3367 calls were not responded to.
Of those, more than 1000 requests for assistance by ambulance staff were declined by fire communication centres because there were no first responders.
In 21 of the red calls there were delayed response times of between 10 and 29 minutes.
NZPFU national secretary Derek Best said he would investigate whether co-responders should formally attend red calls but said training and workloads had to be considered.
Best acknowledged there was a gap in the service and said the irony of the situation was that red call patients had a better chance of being saved by earlier treatment than a patient triaged purple.
"I've got no doubt that sooner or later members in the main provincial and metropolitan areas will be dealing with red calls because the ambulance simply can't cope with the situation."
St John assistant director of clinical operations Dan Ohs said there were several circumstances where FENZ might not have an appropriate resource and this was different to refusing help.
He said on red calls where St John requested a co-response but FENZ did not turn out, St John understood "at times the volume of incidents would exceed the volume of available"resources.
Lynette Blacklaws, of First Union which represents paramedics, said if co-responders were free, paramedics wanted the help.
"I guess if they could and there was someone available I'm sure it would be a much appreciated assistance because the ambulance service does struggle to get people to reds in a timely fashion."
The MOU will be reviewed in December.
