Patients in regional Victoria are languishing in some emergency departments for twice as long as the statewide average, while others endure lengthy waits for elective surgery.

Doctor groups say the stark differences in care are due to inadequate staffing at some regional hospitals, resources failing to keep up with a growing population and patients delaying medical treatment due to GP shortages.

The latest health performance data from April to June reveals that patients at Ballarat Base Hospital, University Hospital Geelong, Latrobe Regional Hospital and Bendigo Hospital are waiting between 28 and 39 minutes to be treated in emergency departments compared with a statewide average of 17 minutes.

Australian Medical Association Victorian vice president Dr Simon Judkins, who works in northern Victoria, said hospital resources had not kept pace with growing regional populations.