Environment Protection Authority (EPA) figures released in the lead-up to the summer fire season show 49 people were penalised for littering from their vehicles across the region in the 2008-09 year.

At $234 for every offence , fines totalled almost $11,500.

During the same period, 19,465 fines were issued statewide, 90 per cent for discarding lit cigarette butts.

In the south-west, the most offences were detected in the Warrnambool City Council area, with 29 motorists reported for careless littering.

Next was Moyne Shire, where 10 drivers were dobbed in, followed by Southern Grampians Shire, with eight offences. Only one litterbug was caught in the act in each of the Corangamite and Glenelg shires.

The EPA and the Country Fire Authority have warned against flicking butts onto roadsides.

EPA environmental services director Bruce Dawson said people driving away from metropolitan areas needed to be aware that the country they were driving into could be tinder dry.

"That cigarette out the window (has) huge potential to catch fire," he said.

Authority chief executive officer Mick Bourke said throwing butts out windows was "absolutely reckless".

"If you light a fire that way you are potentially committing an act of arson ? certainly proceeding with reckless intent," he said.

Those caught throwing litter from vehicles face the $234 fine or can have the matter dealt with in court.

Witnesses should contact the EPA on 1800 548 837 or at www.reportlitter.com.au