Doctors are demanding a fairer system to determine how much people pay for a doctor's visit.

General Practitioners are able to access government subsidies, and doctors who are classed as treating "high needs" patients get more money.

However, this means there can be a huge cost difference from one doctor to the next. In some areas, such as Wellington, one doctor can charge $20 per appointment, while another could charge $60.

Tim Malloy, President of the Royal New Zealand College of GPs, maintains the system isn't actually helping those that need it most.

"It is not a flexible scheme," he said.

"Those people who can afford to purchase primary care can do so, and those people who are the greatest in need should get the maximum benefit from the government's level of subsidy."