The new Eircode postcode system has been dealt another blow after Siptu urged health authorities not to introduce its use for ambulance professionals.
It urged the management of the National Ambulance Service and the Health Service Executive (HSE) not to use the system until the new postcodes have proved to be "fit for purpose."
The launch of Eircode has been marred by controversy, with many experts claiming the €27m project is "not fit for purpose".
Siptu's health division organiser Paul Bell said it had been contacted by many of its members who have expressed major concerns at the rollout of Eircode.
"Our members have stated that they will use any system as long at they can be assured that the system is fit for purpose and has the confidence of the general public," Mr Bell said.
"Despite claims that ambulance professionals should use satellite navigation systems to get to the scene of an emergency, that approach has been deemed to be unreliable in the UK.
"In some cases its use has resulted in tragic circumstances that could have been avoided," he said. "Currently, there are two command and control rooms which direct ambulance personnel to the scene of an accident anywhere in the country.
"That is the most effective way of dealing with an accident or emergency. Addresses are based on a directory supplied by An Post, which has the most up-to-date database. I would expect that to continue," Mr Bell stated.
proven
"Our members expect the managers of the National Ambulance Service and HSE to only introduce the Eircode system when it has been fully proven to be fit for purpose.
"We believe that this can only be after the system has proven itself to be accurate and workable when used by other sectors prior to its introduction for use by ambulance professionals responding to emergency calls.
The new system, which was proposed over a decade ago, assigns a unique code to some 2.2m homes. It is at the full discretion of the householder if they wish to use their new code.
But, it may be requested by some emergency services, online shops or couriers.
Some freight companies, couriers and emergency service operators have all described the initiative as a "waste of time and money".
However, Communications Minister Alex White said the system would prove itself to be effective, adding that it was here to stay.