Leaders of one of the largest groups representing publicans have voted to implement the smoking ban despite calls from its members that they oppose it through measures such as withholding VAT and ignoring the new restrictions.
Instead, the Vintners' Federation of Ireland, which represents publicans outside Dublin, is to mount a legal challenge to the ban.
The decision was taken by the VFI's 60-member national executive council.
The VFI's chief executive, Mr Tadg O'Sullivan, rejected suggestions that the national executive had ignored the views of its grassroots members, and said the legal route was the most effective step to take.
However, at an angry meeting of 1,200 VFI members in Portlaoise last October, many publicans said they were willing to flout the law and risk fines rather than implement the proposed measures. Under the law, publicans could face fines of up to €1,900 and a prison term of up to three months for ignoring the ban.
There were other suggestions at the Portlaoise meeting, such as establishing a fund to pay for fines accumulated by members, withholding VAT payments and standing protest candidates in the local elections.
The decision to implement the ban appears to signal a shift in the position of the VFI leadership.
Mr O'Sullivan told the meeting in October: "Publicans are not policemen...We cannot implement these regulations, they're not capable of being enforced. It's not a matter of breaking the law, it's the law trying to break you."
However, Mr O'Sullivan told The Irish Times in recent days that publicans would abide by the law and that a legal challenge would be taken.
He also said there were "other measures" which could be considered at a later date, but declined to elaborate on these.
The Irish Hospitality Industry Alliance, which represents publicans, restaurateurs and hoteliers, has been less clear over how its members will respond to the ban.
IHIA spokesman Mr Marc Kelleher said while it expected publicans would abide by the law, it was not advisable to place staff in a "position of conflict" when implementing the ban.
"Alcohol is a mood-altering substance. So if someone is after enough alcohol, the reaction can be dangerous. I would be very worried about putting my staff or a family member in a position of asking a customer to refrain from smoking in these circumstances," Mr Kelleher said.
The IHIA is also planning to take a legal challenge. It says exemptions announced by the Minister for Health discriminate against bar workers.
There is still no official implementation date for the ban. A spokeswoman for the Department of Health said the Minister was expected to make an announcement in January on the start date. It is expected this will be in March, three months later than originally signalled.
