Talks have begun at the Labour Relations Commission in an attempt to end the dispute at Fáilte Ireland.
Pickets were placed on the offices of the national tourism authority for a third day because of a row over relocation.
Last night SIPTU had warned the dispute could worsen as staff from other sections prepared to join the dispute unless third party talks took place.
Both sides are now attending the Labour Relations Commission but pickets remain in place.
SIPTU placed pickets on the Pembroke Row offices of Fáilte Ireland on Monday after claiming staff who had refused to move premises had been locked out.
The union said negotiations on the move to Amiens Street had not been completed and management pressed ahead.
However, Fáilte Ireland said the move to Amiens Street had been backed by the Labour Court last year and the deadline had already been moved to address concerns of staff.
The authority had been operating three offices in the capital since Bord Fáilte merged with CERT three years ago.
Some staff have already relocated to Amiens Street but SIPTU said staff in the marketing division had not been given a chance to resolve issues connected to the move.
