Dublin City Council has insisted it has "no legal role" to play in the dispute over union recognition at the company that collects the capital's "green" bins.
Bin collections across the city have been disrupted this morning as staff at the council's cleansing department held a half-day's strike in support of workers at Oxigen Environmental, which is under contract to Dublin City Council.
Oxigen is refusing to negotiate with SIPTU, although the company says it will not prevent workers joining a union. The company has also denied allegations of "bullying and harrassment" made by SIPTU.
Council staff have this morning joined more than 50 workers at Oxigen who have been picketing the company's depots for almost four weeks.
SIPTU wants the Dublin city manager to intervene in the dispute, insisting commitments were given to the trades unions in 1997 in relation to the use of contractors.
However, a spokeswoman for Dublin City Council told ireland.comOxigen's refusal to negotiate with SIPTU was not the council's responsibility.
"It's a private company," she said. She said the 1997 agreement "did not include making it the council's responsibility to make sure union representation is in place".
"We don't have a legal role to play. Our legal role was very clearly defined when the contracts were signed."
The spokeswoman said the council knew nothing of the dispute until strike notice was served by SIPTU last week.
Dublin City Council has said it cannot guarantee the collection today of all bins that would normally be collected on a Thursday. But the spokeswoman said householders should leave their bins out as normal.
She said the council hoped "not to miss people" but would not know the full outcome of this morning's dispute until later today.
Today's dispute comes on the back of weeks of disruption of bin collections throughout Dublin city and county due to protests by those opposed to bin charges.