It is part of a campaign by the General Practice Owners' Association (GenPro) whose members include more than 400 general practices and urgent care providers to address staff shortages and underfunding.
GenPro chair Dr Tim Malloy said a lack of funding, workforce shortages and increasing demands were placing essential family doctor services at risk.
It put pressure on the rest of the health system and directly impacted patient's health, he said.
"It means in lots of places around New Zealand people are waiting weeks to see their family doctor, as General Practice clinics are reducing their hours and reducing services," Dr Malloy said in a statement.
The campaign includes billboards and a report called "On The Brink" which sets out a nine-point plan on boosting support of GP services.
People are also being asked to send postcards to the minister and to sign a petition.
Dr Malloy said a 3 percent funding increase in July with inflation at more than 7 percent and rising living costs had been a massive blow to General Practice.
That equated "to a real-terms funding cut" on 1 July, Dr Malloy said.
"Our essential local nurses and doctors have been undervalued and underappreciated. They have had enough, and patients are at risk as we face an unprecedented exodus from the service."
General Practice had struggled with historic underfunding and now doctors and nurses did not want to work there and were better paid if they opted to work in public hospitals or in Australia, he said.
The government was investing billions in health bureaucracy but had lost its focus on essential front-line services, Dr Malloy said.
The open letter to Health Minister Andrew Little described general practice services as "stretched and under threat".
It called for immediate action from the government to address the crisis and to work to develop a clear plan for the future of family doctor services.
A 2020 survey found that 58 percent of GPs planned to retire in the next 10 years and Dr Malloy said it was very concerning that there was no plan in place to replace them.
"Until primary care doctors and nurses are paid as much as their overseas and secondary colleagues, General Practice will be in crisis," he said.
The general manager of Three Rivers Medical Centre in Gisborne which has nearly 20,000 enrolled patients, half of them Māori, said it was unacceptable that doctors were being forced to provide services to vulnerable populations "on the smell of an oily rag".
Michelle Te Kira said there were challenges due to underfunding and gaps in the general practice model.
"The methodology used to allocate funding is flawed and confusing, and we are being presented with more complex patient needs that cannot be solved in a 15-minute appointment model," she said in a statement.
It was critical to be well-funded and to have appropriate numbers of family doctors to be able to provide adequate safe services and high quality primary health care, she said.
RNZ
