Victoria's health department will conduct a review over fears regional patients are being charged for free and urgent medical treatment.

Victoria has ordered a review into whether patients have been wrongly charged for urgent medial treatment at country hospitals.

It follows reports a patient, who had previously suffered a heart attack, was charged for a later visit to Colac Area Health for chest tightness.

Health Minister Jill Hennessy has ordered the health department investigate whether the practice - in breach of national rules prohibiting public urgent care centres from charging for treatment they already provide - is occurring elsewhere.

"Patients should not have been charged for services provided by Colac Area Health and we're putting a stop to it," she said.

"We also expect any patients erroneously charged will be reimbursed."

Patients at urgent care centres can only be charged if an external practitioner is brought in to provide treatment.

Federal Health Minister Greg Hunt and Rural Health Minister Bridget McKenzie have written to Ms Hennessy over fears people in the regions are being "unfairly disadvantaged" when it comes to accessing medical treatment.

"We are concerned this practice is widespread across regional Victoria and subsequently concerns have been raised with me about patients facing the same costs in public hospitals in Nhill, Casterton and Ararat," the letter said.