Joint social welfare-Garda checkpoints "are not the answer to everything" and will be relatively few in number, the secretary-general of the Department of Social, Community and Family Affairs said.
The measure was included in this year's Social Welfare Bill. It allows Department inspectors, when accompanied by a uniformed garda, to stop a vehicle suspected of "being used in the course of employment or self-employment" and question the occupants.
"Pilot" checkpoints were operated in the previous year. The Minister, Mr Ahern, said these checkpoints had led to 118 social welfare claims being disallowed, giving savings of £350,000.
The checkpoints involve gardai, Customs staff and Department inspectors. The gardai check for road tax and insurance, Customs officers for illegal imports and the Department inspectors for PRSI numbers and other information.
However, they have been controversial, with objections from the Irish Council for Civil Liberties, the Irish National Organisation of the Unemployed and opposition parties.
Mr Eddie Sullivan, the Department's secretary-general, told The Irish Times that the idea came from the Gardai.
"We did find them useful," he said, but "there will be relatively few."
He said the move was part of the continuing search for mechanisms "to get at abuses of the system".
Last year the Department's "control" activities generated gross savings of £164.29 million in payments. In addition, inspections of employer records identified arrears of PAYE/PRSI amounting to £12.54 million.
During the year 243 cases of fraud were passed to the Chief State Solicitor's Office for prosecution. Altogether, 160 cases were brought to a conclusion and all resulted in convictions.