Most affected are the city's western, inner northern and south-eastern suburbs according to a heat vulnerability map produced by the university's Cooperative Research Centre for Water Sensitive Cities.
The centre's Professor Nigel Tapper said it was based on factors such as lack of tree cover, housing type, residents' age, health and socio-economic status.
"Our research found a clear association between suburbs with extreme heat vulnerability and the number of hospital emergency visits or ambulance call-outs on extremely hot days," he said.
"We found key factors that raised the risk of sickness or death in heatwaves included older people living alone, ethnicity and the proportion of land covered by buildings that leads to excess urban warmth."
Areas at low risk included leafy eastern suburbs like Toorak, Kew, Glen Iris and Box Hill, as well as bayside places such as Hampton and Beaumaris.
But well-to-do Brighton is considered high risk because of the high concentration of elderly residents.
With temperatures set to soar over the next few days, Prof Tapper said heatwaves were a major cause of death in Australia, with 374 deaths linked to Melbourne scorchers in January 2009.
"The maps can be used for emergency response planning by hospitals, the ambulance service and local government to protect vulnerable residents and to plan for the future," he said.
Water Sensitive Cities centre chief executive Professor Tony Wong said urban street monitoring showed that the temperature a person felt could be up to 18 degrees lower around midday in areas with tree shading.
"We should be planning more green spaces and planting more trees in the high vulnerability areas," he said.
"Water planners and town planners need to work together to reduce local temperatures."
news.com.au 5 Feb 2013