The change follows an investigation by Victorian Ombudsman Deborah Glass, prompted by a complaint about Ambulance Victoria.

The ombudsman's office reviewed 120 cases in which Ambulance Victoria invoiced people for treatment without transport.

In one case, a man was billed $519 after an ambulance was called to transfer him from a medical clinic to Bendigo Hospital.

Ambulance Victoria is only believed to have recorded the man's vital signs.

"It is not clear if this was from their own assessment or that of the medical clinic," the ombudsman's report stated.

The man travelled to Bendigo in his mother's car after she realised they did not have ambulance cover.

Ambulance Victoria issued 17,758 invoices for treatment without transport in 2017-18.

"There were people being invoiced for ambulances called by well-meaning friends or strangers where transport wasn't required," Ms Glass said of the cases her office reviewed.

"Neither the Good Samaritan caller, nor the injured party, expect to receive a bill."

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A Victorian man injured in an altercation made the original complaint.

He said he was not informed he would be invoiced $519 for allowing paramedics to assess him and clean his wounds.

The ombudsman's office said the ambulance was called by a third party, without the man's knowledge.

Ms Glass accepted that it was the role of paramedics to respond to medical emergencies, not to get involved in discussions about fees.

"It is also not unreasonable for people to be informed that an assessment, including receiving unsolicited 'reassurance', might cost them over $500," she said.

She said several cases of disputed invoices raised questions about Ambulance Victoria's exercise of discretion.

"Or more accurately, the lack of discretion showed in cases where the fee was plainly unfair," Ms Glass said.

"Ambulance Victoria provides a dedicated professional service for which hundreds of thousands of people are grateful; the changes to their charging policies will make it a fairer one."

Ambulance Victoria chief executive, Associate Professor Tony Walker welcomed the report and accepted all of the recommendations.

"We are committed to continual improvement and are changing our billing practices to ensure patients are appropriately billed for the care they receive," he said.

He said Ambulance Victoria would stop charging people for treatment without transport where an ambulance was called by an unknown third party and the patient did not know or could not have reasonably consented to an ambulance being called, including when an ambulance was called by police.

Other changes included splitting charges evenly among patients when paramedics had treated but not transported multiple patients, and ensuring billing staff considered the unique circumstances of each case and exercised discretion when dealing with disputed invoices for treatment without transport.

"Ambulance is not a free service in Victoria. Patients who do not have a membership, concession entitlement or other coverage are required to pay for the high quality care they receive," Associate Professor Walker said.

"We will always provide all our patients the highest quality care irrespective of whether or not they have the capacity to pay for the service."

The invoice that led to the original complaint has been cancelled.

Ambulance Victoria has promised to refund all patients with evidence of paying for treatment without transport in similar circumstances over the past 12 months.

Associate Professor Walker said affected people could call 9840 3530.

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