Health Minister Mark Butler has accused pharmacy peak bodies of scaremongering on upcoming changes to prescription medicines.

As many as six million Australians will be able to pay less for medicines from September, with the government to allow people to buy two months’ worth of subsidised medicines on a single prescription.

More than 300 medicines will be included on the list, including treatment for conditions such as heart disease, cholesterol, Crohn’s disease and hypertension.

The medicines will be phased in during three stages, with the first on September 1.

The federal government says the change will save general patients up to $180 a year, and concession card holders up to $43.80 a medicine.

Between fewer visits to the GP and pharmacist, the total saving to patients from the measure will top $1.6 billion over the next four years.

Pharmacists, however, have reacted with fury, warning the changes would lead to wide medicine shortages and compound those already in place.

Pharmacy Guild president Professor Trent Twomey said there were already 472 medications in Australia that were critically short in supply or unavailable.

“We’ve got more medicine outages in Australia than we’ve ever had in the history of the pharmaceutical benefits scheme,” Professor Twomey said.

“The government needs to stop worrying about a glossy announcement, a pre-budget promise about helping the cost of living, and get the basics right first. Which means making sure everyone can get at least one box.”

He said the changes could lead to further medicine shortages for patients.

“I’m all for cost-of-living relief and a cost-of-living measure, but this, unfortunately, is just smoke and mirrors,” he told ABC TV on Wednesday.

“If you don’t have the medicine in stock, how do you give double nothing? Double nothing is still nothing.”

Mr Twomey said more than 470 medicines in the country already had critical shortages or were completely unavailable.

But Mr Butler denied the claims on Wednesday.

“This is not going to change the number of tablets dispensed in a given period of time, it’s simply going to mean that people can get two boxes at a time instead of having to get one box and come back twice as often,” he said.

“I really would caution against some of the scare campaigns being put by the pharmacy lobby group.”

Of the 325 medicines as part of the list, seven had shortages, Mr Butler said.

He said the $1.2 billion the government estimated would be saved over the next four years, would be reinvested into community pharmacy health programs.

“Almost one million Australians go without a medicine or defer getting a script filled because of cost. We know that dropping the price of medicines is better for patients’ compliance with their medicines that their doctor has prescribed,” he said.

Under the government’s changes, doctors will still be able to choose to write a prescription for a one-month supply for patients, rather than two.

Mr Butler said the proposal would not affect supply for the medicines on the list. He said many countries made three months’ supply available at a maximum.

“We’ve decided to go with two months at the moment. We think that’s the right balance between the interests of patients and support for a strong community pharmacy sector,” he said.

Australian Medical Association vice-president Danielle McMullen welcomed the changes to prescriptions.

“At the time we’re talking about so many cost-of-living pressures, this will really ease the burden on patients across Australia,” she told Seven’s Sunrise program.

“There are some situations of shortages in medicines at the moment but there will be a staged approach to this announcement to ease the burden on the shortages.”

– with AAP