Speed camera operators working for GoSafe will strike on 28 September in a row over pay and conditions amid union allegations that shifts are so long that staff use plastic bottles for toilet breaks.
The consortium based in Listowel operates roadside speed monitoring vans under a State contract from the Department of Justice and Equality reported to be worth €115.5m over five years.
According to SIPTU, which claims to represent over 50% of GoSafe operators, some are rostered on shifts up to 11 hours long.
However, SIPTU official Brendan Carr said that because operators must keep their van within sight, they frequently cannot take toilet breaks away from the vehicle and are forced to urinate into bottles.
He said that for legal reasons, despite being officially allowed to take breaks, the fact that operators may have to give evidence in court means they have to be in "operational charge" of both the speed van and its camera equipment throughout the shift.
Mr Carr acknowledged that next Saturday's strike could affect safety on the roads, as motorists might be more inclined to take risks with speed but said staff were taking the action as a last resort.
He accused GoSafe of refusing to implement a Labour Court recommendation that SIPTU should have sole negotiating rights for staff, adding that the company insisted it would only negotiate with the workforce through its in-house representative forum.
He called for no further Government contracts funded by the taxpayer to be issued to companies refusing to engage with the dispute resolution mechanisms of the State.
Mr Carr accused the Minister for Justice and Equality Charlie Flanagan of refusing to intervene, adding that the fact that this situation involved a contract awarded by the Department responsible for justice and equality issues was "immoral".
The Department of Justice and Equality responded by reiterating that Minister Flanagan cannot intervene in a dispute between GoSafe, its employees and SIPTU, adding that the contract was between the Minister, the Commissioner of An Garda Síochána, and GoSafe (trading as Road Safety Operations Ireland).
It said the Minister urges all those concerned to seek a positive resolution to this dispute through the appropriate channels.
In a statement, the Department said that the safety camera network makes a significant contribution to road safety by directly influencing and promoting responsible driver behaviour.
It noted that last year, Ireland was the second safest member state in terms of road deaths per million inhabitants, and had seen the lowest number of fatalities ever recorded here.
However, it accepted that effective road traffic enforcement was critical to make Irish roads as safe as possible for all road users, and that maintaining progress in road safety requires ongoing attention.
Garda management intends to issue 2,000 mobile devices by the end of the year to frontline gardaí, with a focus on roads policing in line with target contained in the implementation plan for "A Policing Service for the Future".
It said that potential further improvements as part of the ongoing process of Garda reform include the rollout of the Mobility project as recommended by the Commission on the Future of Policing.
The 24-hour strike will commence next Saturday at 6am.
A GoSafe management member contacted by RTÉ declined to comment.