Shell’s customer service centre has received 290 calls relating to the quality issue.

Trouble erupted after an unknown quantity of LPG with higher than normal residues was supplied by Shell to service stations in western Victoria and northern and western Melbourne.

Some of the gas was delivered to Bendigo.

Twenty-four Coles Express and between 25 and 30 BP service stations temporarily suspended gas supplies to customers.

Some Caltex service stations were also affected.

Businesses authorised to equip and service LPG vehicles are faced with a huge workload.

Brian Dunn Ford is one of many trying to get motorists back on the road as quickly as possible.

"It has put us under extra pressure," dealership principal Philip Palma said.

"You’ve got your normal jobs like services booked in, then you’re getting six or seven towed in (affected by gas) each day."

Mechanics say the cost of fixing vehicles damaged by the contaminated gas will vary.

"New injection-style systems suffer more than older systems because they have more precision components in them," McPherson’s Service Centre owner Graeme McPherson said.

Motorists with systems that require only a clean-out will pay about $100.

Vehicle owners with newer systems that have been substantially damaged could pay up to $2000.

North Bendigo resident Richard Sullivan filled the gas tank of his 2004 Ford Territory Ghia on June 22, and booked the vehicle into Brian Dunn Ford next day.

"I started it on petrol," he said.

"With gas it’s got to be warm enough to switch over. When I did, it would stall." The car, which he had modified two months ago for $3300 (after a $2000 government rebate), is off the road and waiting for parts.

"The lines, converter and injectors need to be replaced." This may cost up to $2000.

Shell and BP (whose LPG is supplied by Shell) have said they will pay the repair costs for damage resulting from bad gas.

Customers must have proof of purchase of the gas, and bank statements will be accepted by both companies.

"If the vehicle has been repaired we will need a report from the mechanic," BP media manager Chandran Vigneswaran said.

For legitimate claims BP will also compensate for loss of income and use of a hire car.

"It’s not something we take a long time to sort out," Mr Vigneswaran said.

"We don’t want customers to have any additional concerns."

Shell spokeswoman Claire Wilkinson said the company always refunded legitimate claims.

"We will need an invoice from the repairer.

"For legitimate claims we will also pay back the cost of the fuel.

"If the vehicle had to be towed we will pay the towing costs."

BP customers can contact 1300 130 027.

Shell customers who bought LPG from June 17-28 should phone 131 618.

Any LPG being sold at service stations is now safe to use.

All service stations were expected to be selling gas by the end of the week.