Road safety may be under threat in a week as speed camera operators are set to strike for 24 hours.
Workers employed by GoSafe, which is contracted by the State to operate the speed camera service, will begin a stoppage at 6am next Saturday.
Last night, Siptu official Brendan Carr warned they will ramp up the industrial action to an all-out strike if there is no "positive outcome".
The workers plan to walk off the job due to a dispute over their working conditions.
They are seeking a pay rise and claim they do not get adequate breaks. They also claim toilet facilities are not sufficient.
One of the workers, who wished to remain anonymous, said that he and his colleagues "absolutely slow traffic down in dangerous areas" but felt they had to strike to further their claims. He said pay is around €12 an hour, but there is a small subsistence allowance and shift pay.
Mr Carr said the staff can be confined to their van for up to 11 hours while conducting their duties. He said the Labour Court recommended that the employer should recognise Siptu, but this was ignored by management.
"This dispute highlights the unacceptable practice of Government departments issuing contracts for State services to companies who refuse to respect the industrial relations bodies of the state," he said.
GoSafe did not respond to a request for a comment.
Meanwhile, the Garda press office had not responded to a request about contingency planning at the time of going to press.