Three men have been convicted for their involvement in an NCT scam first exposed on RTÉ's Prime Time in 2011.

In the scam, cars previously deemed unroadworthy were passed.

Stephen Rooney, 37, Alan Richardson, 28, and Vincent Brunton, 34, were arrested and charged following a garda investigation in the wake of the RTÉ programme.

At Dublin Circuit Criminal Court, Judge Gerard Griffin imposed sentences of three years with two-and-a-half years suspended on Rooney and Richardson.

He suspended the entirety of a three-year term for Brunton, who he said was on the bottom rung of the ladder in the scam.

The court heard previously that Richardson, who was working as an NCT inspector, was contacted by his neighbour, Rooney, and asked to pass two Toyota Carinas.

Both vehicles had previously failed the test and were scheduled for a re-test.

The men were to get €100 between them for their role although no money was ever exchanged.

Richardson then asked NCT tester Brunton to pass one of the vehicles as roadworthy.

A fourth man, Darren Meehan, 40, of Delemere, Enfield, Co Meath, was approached to pass the second vehicle.

He received a two-and-a-half year suspended sentence last month for his role after he pleaded guilty to producing a false NCT certificate.