Doctors and public health experts are calling for the Victorian government to urgently review its management of heatwaves as the death toll from this month's record-breaking period appears to climb.

The Victorian Institute of Forensic Medicine, which works with the State Coroner to investigate reportable deaths, said that as of Friday it had recorded 139 deaths in excess of the average expected between Monday, January 13, and Thursday, January 23.

Dr Liz Hanna said it was 'unfathomable' that Victoria had not learnt from the catastrophic 2009 heatwave. Credit:Glenn Campbell

Dr Liz Hanna, a fellow at the National Centre for Epidemiology and Population Health at ANU, said it was ''unfathomable'' that Victoria had not learnt enough from the catastrophic 2009 heatwave, when 374 lives were lost, and the Victorian Greens are demanding a formal inquiry into what they call the state's ''clear lack of preparation'' for periods of extreme heat.

While Institute of Forensic Medicine director Stephen Cordner said he could not be sure the deaths were due to the heat, most of the deceased were elderly people and those with chronic and mental illnesses, who are known to be vulnerable in extreme heat.