The Minister for Health, Micheál Martin, has announced that the smoking ban in pubs, restaurants and most work places will come into force on 29 March.
He told a news conference in Dublin that the ban was a positive, progressive health and safety measure.
Enforcement of the ban will be carried out by 40 dedicated environmental health officers.
They will be assisted by 300 other environmental health officers involved in food safety, and by 100 people from the Health and Safety Authority.
Mr Martin said that those who are caught smoking in an enclosed workplace will be fined €3,000.
The anti-smoking group, ASH, has described the ban as the health initiative of the century.
IMPACT, Ireland's largest public sector trade union, which also represents environmental health officers, has welcomed the announcement.
IMPACT spokesperson, Bernard Harbor, said that the union 'fully supports this important public health initiative'.
'The ban is welcomed by thousands of our members who, in their professional work, see the devastating effects of passive smoking', Mr Harbor said.
The Irish Medical Organisation has also welcomed the ban. IMO President Dr Joe Barry said the ban would discourage young people from starting smoking and encourage smokers to stop.
Vintners call ban 'unworkable'
A spokesperson for the Vintners Federation of Ireland called for Mr Martin to clarify how he expects the ban to be enforced and who will be responsible for policing it.
The VFI also called on the Minister to ensure that if a smoker persists in smoking in a pub, it is the smoker and not the publican that is fined.
The Irish Cigarette Machine Operators Association said that today marked the association's 'darkest day' because of the announcement.
ICMOA spokesman, Gerry Lawlor said: 'All of our members are small business people and this ban, announced today, will have a devastating effect on our lives.'
Ban had been due on 1 January
The ban had been due to be implemented in January, but following amendments, other EU countries were given a period in which to make any objections. However, no objections were received.
From 29 March, smoking will not be permitted in enclosed places of work except for certain exempted locations.
These include: prisons, Garda Station detention areas, St Patrick's Institution for young offenders, nursing homes, hospices, religious order homes, the Central Mental Hospital, psychiatric hospitals, maternity homes, hotels, guesthouses, B&B; bedrooms and third level education residential facilities.