Civil servants working in State agencies may cease co-operating with the Government's decentralisation plans unless changes are made to the consultation process.
Mr Owen Reidy branch secretary of SIPTU which claims to represent more than 1,500 of the 2,500 State agency workers affected by the plans, said it "may have to consider the option" of boycotting a Government-backed survey of staff next month unless the poll allows employees to express their desire to remain in their current posts.
"People should be allowed to express their true interests. Otherwise, we fear that those who wish to stay in Dublin will be treated as second-class citizens, or as an afterthought in the process. That should not happen if the process is really a voluntary one."
Under the Government's plans, civil and public servants will be asked to rank their preferred decentralisation locations in order of preference, from one to 10.
However, they will not be allowed, for the purposes of the Central Applications Facility, to opt to remain in Dublin in their current positions.
Mr Reidy said his members, more than 95 per cent of whom wished to remain in Dublin, were "very unhappy" with the report of the implementation group, chaired by Mr Phil Flynn.
Union officials had arranged to meet the Department of Finance and the ICTU next Monday in what "might be a defining meeting", he added.
SIPTU's decentralisation committee, comprising representatives from the 20 State agencies affected, is due to convene a separate meeting next week to establish their strategy.
IMPACT has also expressed fears over the career prospects of staff who opt to stay in Dublin.
The union, which claims to represents more than 6,000 professional and technical civil servants, said straw polls indicated there would be "serious problems" in filling vacancies voluntarily.
