TASMANIA'S rising petrol prices have led to an augment in the number of service station customers driving left without paying.

The trend might force service station operators to make customers fund their fuel in advance, warns Tasmanian Automobile Chamber of Commerce chief Malcolm Little.

Motorists in Tasmania's urban centers should pay up to $1.47 a liter for unleaded petrol that has pushed the cost of a full tank for the average family sedan above $100.

"Obviously, with the increasing price of fuel it's becoming more of a burden on people and some people will resort to illegal actions," Mr. little said.

"In terms of dealing with it, if it continues, the industry has a number of options available. One of those, the more significant, is to go to pre-pay."

"That involves pumps being turned off and people having to pay for fuel before pumps are turned on and they're able to fill their car."

In Western Australia, petrol stations have suffered so many petrol thefts they now use security guards to look after drivers filling their tanks.