Gardaí are investigating a complaint that two staff members were fired from a National Car Testing (NCT) centre in Dublin for accepting bribes to pass un-roadworthy vehicles and that this practice may be widespread at other NCT centres.

A statement was made to gardaí last week outlining how two NCT employees were earning up to €250 a day passing un-roadworthy cars for second-hand car dealers in return for €50 per car. The individual who made the complaint also said that this practice may be going on in at least two other test centres. Gardaí are now concerned about public safety issues as many of these vehicles were subsequently sold with full NCT certification.

It is understood that the two employees who were fired in recent weeks were caught "red-handed" giving a NCT certificate to the owner of a car that had just failed the test.

Gardaí have been told that it is policy for NCT staff to take in additional cars for testing when there is a cancellation. But on top of this, some employees were contacting car dealers directly when they had spare time and were passing these cars "on the side for cash" regardless of whether the vehicles were roadworthy. The individual who made a statement to gardaí said it was possible for some staff members "to interfere with the test" in order to pass un-roadworthy cars.

It is believed that NCT management has been notified in the past over suspicions that some staff were taking bribes from second-hand car dealers to pass cars.

Testing of passenger cars in Ireland has been provided by National Car Testing Service Ltd, wholly owned by SGS Ireland Ltd, since January 2000 but the company's contract expires at the end of the year. Despite repeated media queries, the company declined to comment when contacted last week.

The Sunday Tribune revealed three weeks ago that two NCT staff members had been fired for accepting bribes from car dealers to skip the queue. A spokeswoman told this newspaper on that occasion that she could not comment on issues relating to employees.

"We can't confirm or deny this information. There is no question in relation to the integrity of the test," she said.

In February, the Road Safety Authority announced that the contract for the provision of the NCT from 2010 to 2019 was awarded to Applus+, which will assume responsibility for the provision of national car testing on 4 January 2010.