St John Ambulance is investigating claims that a woman stung dozens of times by wasps wasn't able to get through to 111, despite ringing numerous times.
The victim claims the 111 service initially told her an ambulance couldn't reach her because her address didn't exist.
St John have confirmed they are investigating the matter.
Janet Kelland, 65, was flown to hospital on Monday after stepping into a wasp nest on her rural Taumaranui farm.
She was stung at least 50 times on the head and right leg, and had to walk 45 minutes for help after being swarmed.
Federated Farmers have now raised concerns that the 111 service failed Ms Kelland when she needed it the most.
"Given the 111 service is a rural lifeline, Federated Farmers was troubled to learn Janet Kelland struggled to get through for upwards of 30 minutes," Federated Farmers Rural Security spokeswoman Katie Milne said.
After she managed to get away from the swarm, Ms Kelland made for the farmhouse - a trek that took 45 minutes.
On the walk home she said she eventually managed to phone St John which sent an ambulance and also alerted the Waikato Westpac Rescue Helicopter.
She was airlifted in a stable condition to Taumarunui Hospital, where she spent the night.
"After getting clear, Janet rang 111 and sometimes it would ring she told us and sometimes there was silence," Ms Milne said.
While she accepts cell reception can be random in rural areas, Ms Kelland says she has reception on her farm and good reception from where she tried to call from.
The farmer told Federated Farmers that it took 30-minutes before she got through to an operator.
"Even then after asking for an ambulance she was cut off," Ms Milne said.
"She did get through but when she gave her address the operator insisted it did not exist.
"While Janet resorted to some agricultural language, who could blame her given she was in agony?"
Federated Farmers says Telecom/Spark's Telecommunications Service Obligation is relevant in this case because it must answer 111 calls within 15 seconds.
The farmers' group is now calling on the telecommunications giant to investigate what happened on Monday. The mapping software being used by the ambulance call centre also needs reviewing, it said.
"A farmer repeatedly stung by wasps could have died for want of a connection," Ms Milne said.
"Clearly there are several issues that need to be looked at."
A spokeswoman for Telecom/Spark said while they haven't received a complaint, or yet been able to speak with Ms Kelland, it is something that are taking "extremely seriously".
"The information we had initially did seem to suggest she was out of coverage," the spokeswoman said.
"But there has been conflicting reports on that, so we are very keen to speak to her directly."
A St John spokesman confirmed the territory manager for Taumaranui was aware there had been an issue and was looking into it.
""e are currently investigating the incident," the spokesman said.
"We're not in a position to comment further on the allegations, while they conduct the investigation," he said.