SIPTU has called for the resignation of the Minister for Enterprise, Trade and Employment Michéal Martin, after he announced a change in the mandate of Shannon Development.
In a statement today Mr Martin said the company would cease certain tourism and enterprise support activities and concentrate instead on supporting economic growth in less developed parts of the region.
He said the company would retain responsibility for all industrial property in the Shannon region and for the management of the Shannon Free Zone.
However, the union accused the Minister of a breach of faith by announcing changes that had yet to agreed.
SIPTU General Secretary, Joe O'Flynn, said: "Following our last meeting, the Minister promised he would refer to us again before any announcement was made."
"Only last week, I contacted the Minister's office to be told that the review process was continuing and that no announcement in relation to Shannon Development would be made before September."
Under Mr Martin's plan, Shannon Development would pass a number of its economic development roles on to Enterprise Ireland and the IDA.
These changes were taking place against the background of the decentralising of the Headquarters of Enterprise Ireland to Shannon and the formation of a newly independent Shannon airport, he said.
The Minister said the role of Shannon Development had evolved as circumstances in the region changed.
Mr Martin said: "I have asked the company to submit specific proposals to me as to how they propose to address the needs of [underdeveloped areas]."