SIPTU has rejected initial proposals put forward in relation to Dublin Bus at a meeting between union representatives and officials from the Department of Transport today.
SIPTU vice president Mr Brendan Hayes said in a statement this evening: "Discussions will, however, continue under the auspices of the Labour Relations Commission to try to arrive at an agreed way forward for Dublin Bus and public transport services within the Dublin area."
"The talks are scheduled to resume tomorrow morning and no further statements will be issued," he said.
The talks on the restructuring of CIÉ began today amid acrimony over a new study into the Dublin bus market commissioned by the Department of Transport.
The National Bus and Rail Union had said it was not aware of the study, which is due for completion next year. However, sources in the other CIÉ unions dismissed the claim that the NBRU did not know about the study as "theatrics" today. SIPTU officials were made aware of the study in late April.
The Labour Relations Commission meeting today is expected to mark the first of five days of intensive talks.
Unions have been angry at the Minster for Transport, Mr Brennan, in the past for failing to consult them about his plans to split up the CIÉ group. The minister's plans include the introduction of private operators on some Dublin routes.
The Dublin Transportation Office review addresses issues due to be discussed which could render negotiation pointless, unions say.