The big four companies, Shell, BP, Mobil and Caltex, sell E10 petrol - 10pc ethanol and 90pc unleaded petrol - at more than 670 sites throughout NSW, Queensland and the ACT.

A BP spokesman said the introduction of E10 began in Queensland in March 2006, and was introduced to NSW last July.

Since then, more than 300 million litres of E10 have been sold, with total sales expected to exceed 500ML by the year's end.

The ethanol-blend petrol is discounted by three cents a litre under the Biorewards scheme, and so far the company has not received "one customer complaint since we have been selling E10", the spokesman said.

Shell and its Coles Express brand have 174 sites selling E10 across the country.

A spokeswoman said that the Coles service stations have seen an increase in ethanol fuel sales of about 50pc in recent months.

Caltex now sells E10 at 220 sites in its national network.

"We have invested in storage terminal and service station upgrades in NSW and Queensland to sell increased quantities of ethanol," a company spokeswoman said.

The other big E10 retailers include United Petroleum, which sells the fuel at about 260 sites in the country, and Freedom Fuels, which sells it at about 38 sites.

However, a survey released by AAMI insurance on June 6 found that there is still a reluctance among Australian motorists to use E10, despite its discounted price.

Only 26pc those surveyed said they buy ethanol-blend fuels, with 41pc of drivers saying they were unaware that the biofuel was suitable for their car and 26pc saying they were concerned about possible negative effects on their vehicles.