The cases, some dating as far back as 2012, come as Bega Valley resident Rod Camilleri is taking United Petroleum to the NSW Civil and Administrative Tribunal for more than $12,000 in damages after purchasing 70 litres of contaminated diesel from United's service station at Michelago in January this year.

The tribunal will next hear the dispute in January after United refused to sign documents admitting liability.

Yowrie resident Bruce Dogan suffered a case of fuel contamination from the service station on November 18 last year after filling up with 35 litres of diesel.

While he was covered by insurance, the incident left the pensioner almost $2000 out of pocket and his car written off.

"I would often fill up [at the Michelago United] as it was the closest service station. After I filled up, by the time I got to Cooma, it was very hard to start," he said.

"The mechanic couldn't work out what was wrong with the car and it was taken to Canberra to get looked at it and they found there was water in the fuel tank."

When Mr Dogan rang the service station about the incident, he was told it was the third instance of fuel contamination on the same day.

He now has to drive 40 kilometres to fill up at the next nearest service station.

"I saved about $4 from filling up at the United but it ended up costing more than $12,000 in damage," he said.

Mark Cooper filled up his Volkswagen with premium unleaded at the Michelago service station in 2012. Then he discovered his car's engine had been damaged due to fuel contamination.

"The whole engine had to be rebuilt. The fuel should be filtered before it gets into the bowser," he said.

Jerangle resident Andrew Roberts was forced to pay for thousands of dollars worth of damage to his car after he also filled up with contaminated fuel.

"The car started to blow black smoke all onto the road and getting a bit rattly and also the fuel consumption wasn't as good as it was," he said.

Mr Roberts was left to pay $8000 as a result of the contamination, despite being insured.

"While water was found in the fuel system, it was difficult to prove anything," he said,

United Petroleum did not respond to questions from The Canberra Times before deadline.

In the past financial year, there have been 270 cases of fuel contamination in Australia, 21 of them in the ACT.

David Webster is the principal of Cooma Diesel Service, which specialises in repairing diesel engines after fuel contamination cases.

He said he estimates he deals with up to 13 cases of fuel contamination every week, with water getting into the fuel supply the most common cause.

"Almost any fuel bowser can have water at any given time, modern vehicles don't like water," he said.

"Fuel systems are so intolerant because it's so precise."

While some service stations have more cases of fuel contamination than others, Mr Webster said any service station could potentially be affected by contaminated fuel.