Taxi drivers are threatening to picket the State's busiest airport in protest at plans by Aer Rianta to introduce a new charging structure for drivers doing business there.
The National Taxi Drivers' Union (NTDU) has warned the Minister for Transport, Mr Brennan, that it will not accept a unilaterally imposed change in charges.
The State airports' authority and three trade unions representing taxi drivers are in talks over the new charging proposals.
Aer Rianta wants to switch from the current system, which involves an annual fee of €75 plus a charge of 70 cents each time a taxi collects a passenger from the airport, to a flat €600 a-year charge.
In a letter to sent Mr Brennan at the weekend, the NTDU stated that Aer Rianta warned it that drivers who had not paid by May 1st would be refused access to the airport.
NTDU president Mr Vincent Kearns warned that the union's members could picket the airport if Aer Rianta introduces the new structure without agreement between the parties.
The NTDU, SIPTU and the Irish Taxi Drivers' Federation plan to ballot members over the proposed charge structure. They distributed flyers to drivers at the weekend informing them of this.
However, both Mr Kearns and the secretary of SIPTU's taxi drivers' branch, Mr Jerry Brennan, told The Irish Times that they were willing to continue negotiating on the issue.
Aer Rianta says the large number of taxis who regularly operated from the airport rank already pay close to €600 a year when taking the combined €75 annual charge and 70 cent a-trip levy into account.
Under the current system, drivers making 750 pick-ups a year, just over two a day, would match the proposed new charge.
A spokesman said that the current system had security implications for Aer Rianta. Taxis queue for entry to the rank in a relatively isolated section of the airport and pay cash at a booth, which is open from early in the morning to late at night.
He confirmed that Aer Rianta hoped to introduce the new system next month.
The spokesman acknowledged that the introduction of the new system could reduce the number of taxis operating out of the airport. However, he pointed out that there was already overcapacity there. Mr Kearns and Mr Brennan confirmed this.
Taxi drivers will be offered the option of paying quarterly but this will raise the cost.
Mr Kearns told The Irish Times that Aer Rianta had proposed quarterly payments of €180, bringing the total annual charge to €720 for those paying by instalments. However, it is understood that this may be up for negotiation.
SIPTU and the NTDU are likely to demand that Aer Rianta invest further in the waiting area it created for taxis before they enter the airport's rank as part of a deal that would involve the drivers accepting the new charges.