Due to the recent and devastating floods in northern Australia there are likely to be shortages in the supply of ethanol in coming weeks, ACCC commissioner Joe Dimasi said.

While the extent of damage is unknown, the floods have caused the loss of crops used in ethanol production and the ACCC has been informed that there are disruptions at key processing plants. This will likely result in a shortage of the domestic supply.

"The supply shortages may lead to reduced availability of ethanol blended fuels (such as E10) across Australia and mean that motorists may find that fuel pumps which carry ethanol blended fuel are closed or out of order," Mr Dimasi said.

The ACCC is also warning retailers about their obligations under the Competition and Consumer Act 2010 during this time.

"Fuel retailers must be particularly vigilant in the coming weeks and take all reasonable steps to ensure that consumers are not misled," Mr Dimasi said.

"The ACCC encourages retailers to be clear in their signage and labelling at their service stations, including on price boards and at the pump, regarding the availability, or lack of, ethanol blended petrol."

The ACCC indicated in its report, Monitoring of the Australian petroleum industry 2010 which was released in December last year, that Australia may face ethanol supply shortages in the next few years. This is due to a combination of factors including increased consumer demand, enacted and proposed state government mandates and increased investment uncertainty, in part caused by the global financial crisis.