SQM Research managing director Louis Christopher said vacancy rates in these central city locations were climbing quickly.
"I would also like to make a note of warning for the CBD locations of Brisbane, Perth and Melbourne, where for each CBD, vacancy rates are rising at a very rapid rate," he said.
"Those considering investing in the CBDs of these three cities should be strongly aware of this fact."
According to SQM Research, the vacancy data for the capital cities including surrounding suburbs delivered mixed results.
Greater Perth saw the largest increase in vacancies over the year with a rise of 1.1 per cent.
The Brisbane area and Canberra were close behind with increases of 0.6 and 0.5 per cent respectively.
Only Hobart saw the rental market tighten as vacancies fell by 0.4 per cent.
Overall, the national vacancy rate for capital cities climbed by 0.3 per cent in the past 12 months.
"On a month-to-month basis, vacancy rates can be quite volatile and are often moved around by seasonal patterns," Mr Christopher said.
"That is why consideration of the annual change is critical in the overall market assessment.
"On that note, vacancy rates continue their slow rise."
The report suggests the demand is softening as tenants leave the rental market to purchase their own properties.