The carbon tax is expected to have lifted consumer prices by around half a per cent during its first three months of operation.

Economists say the greatest impact has been on electricity prices, though the tax is also believed to have lifted gas prices, council rates and fruit and vegetables.

Still, the carbon tax's effect is expected to be less than a quarter of the spike in prices after the introduction of the GST in 2000.

The Australian Bureau of Statistics will release the Consumer Price Index (CPI) measure of inflation for the three months to September, on October 24.

AAP's survey of 15 economists on Friday revealed a median forecast for the CPI to have risen by 1.1 per cent during the September quarter.