90% of NBRU members have voted to take industrial action in protest at plans by Transport Minister Seamus Brennan to restructure CIE and franchise out a quarter of Dublin bus routes.
The union will stage its first 24-hour strike of all national bus and rail services on Tuesday July 20.
Its next one-day stoppage will take place on Wednesday August 4. Strike action will then be escalated to two consecutive days on August 24 and 25, followed by a three-day strike on September 7, 8 and 9.
It is understood that the Luas service will not be affected as the NBRU does not represent any Luas staff.