A team of researchers across Australian universities say the proposed $7 GP co-payment would have a profound effect on hospital emergency departments.

They say that if even a small percentage of patients are put off going to the GP, accident and emergency waiting times could increase by three hours.

Researchers from a variety of institutions worked together to model outcomes of any patients who decided to go to hospital emergency departments rather than GPs.

Professor of Medicine at the University of Adelaide, Dr Robert Adams, spoke to the ABC about the results.

“If you make one change somewhere in a complex system like a hospital, you can have a number of different consequences, some of which you may not intend to get,” he said.

“If we assume the resources in emergency don't change, so that there's no extra staff, and there's no extra capacity, the wait, if you get four extra patients per hour in, goes up by about three hours on average.

“And the number of people waiting will tend to go up from, say, around nine people waiting in emergency department up to over 30 people waiting emergency department, if you add in these extra people per hour.”

While there is not data yet on how many patients would in fact change their behaviour based on the co-payment, the modelling showed that even if one in 1,000 patients did – average emergency department times would increase from 5.5 hours to 8.5.

Federal Health Minister Peter Dutton said it would be up to state health departments to decide whether they allow people into emergency departments who are not in an emergency situation.