More than 600 pharmacies and 20,000 jobs might be at risk if the federal government follows through with plans to change rules around medicine dispensing.

The Pharmacy Guild of Australia is warning of job losses following the release of an independent report analysing the government's plan to allow up to six million people to buy two months' worth of subsidised medicines with a single prescription.

The policy would apply to more than 300 medicines including treatments for conditions such as heart disease, cholesterol and Crohn's disease.

The report by economist Henry Ergas found community pharmacies could lose more than $4.5 billion over four years under the changes.

Vulnerable communities including the elderly, Indigenous people and Australians living with chronic health conditions could be disproportionately impacted with regional and rural pharmacies the first to close, the report stated.

Pharmacy Guild of Australia president Trent Twomey called on the government to go back to the drawing board.

"Once we've lost this important piece of healthcare infrastructure, we cannot ever get it back," Mr Twomey told reporters on Monday.

Prime Minister Anthony Albanese threw his support behind Australians who require ongoing medicines.

"The logic that someone who has a permanent condition, who will need a particular drug for the rest of their lives ... who can get a script for 60 days rather than 30 days, should pay twice as much, should go twice as often to the doctor, is quite frankly absurd," he told parliament.

Assistant Treasurer Stephen Jones said the government is committed to keeping the price of medicines low amid a cost of living crisis.

"Our number one concern are Australians who we think are paying more than they need to for their medicines," Mr Jones said.

"They're paying too much for those medicines at the moment."

The changes by the government have the backing of consumer, health and doctor organisations including the peak body representing general practitioners, the Heart Foundation, Australian Medical Alliance and Consumer Health Forum of Australia.

Mr Jones said the savings made through the measure will be reinvested back into pharmacies.

But Mr Twomey said the reinvestment would not make up for the thousands of dollars lost by pharmacies.

Mr Ergas in his report recommended the government suspend the implementation of the policy until a review could be undertaken to fully understand the impact the changes would have on pharmacies.