The hour of reckoning for the State's vital operations approach es and the overall mood is one of confidence - among key utilities at least. Millions of pounds and thousands of hours have been spent ensuring a successful changeover of information technology systems to January 1st, 2000.
The problem stems from only two digits being used in many cases to represent the year in computer date fields. For example, 1996 is represented as 96. This has implications when the date field 00, will be interpreted as 1900 causing failure in date-based calculations, sorting and sequencing.
The type of Armageddon once predicted by Y2K pioneers is now believed unlikely to happen, but smaller scale disruptions may cause considerable damage well into the new year.
The biggest concern in Ireland lies with small and medium-sized businesses, and last week the Small Firms Association said it was concerned at the level of inaction.
In its most recent survey, 40 per cent of companies said they had no Y2K contingency plans if something goes wrong, and 90 per cent said they felt the event had been over-hyped.
According to Mr Pat Delaney, director of the SFA, this indifference may have very serious implications as non-compliant small or medium-sized business feed into larger organisations. The end result could mess up an entire supply chain process by upsetting inventory or billing systems.
"Companies relying on other companies may face temporary closure as a result. We would also have particularly worries about embedded chip systems necessary to basic processes, take the example of an elevator operating in a small hotel . . . There is no doubt there will be instances of Y2K failure," Mr Delaney says.
Among the larger utilities the event will be closely monitored by specially appointed "Y2K watch" staff across all sectors. According to Mr Dave Murray, Y2K project director with Eir com, the company is better prepared for Y2K than it was for the network breakdown in November, because this time there will be people in place across the entire company waiting for something to go wrong.
At a cost of £25 million, Eir com has spent the last three years addressing Y2K and latterly investing heavily in contingency and continuity planning.
"We have to assume it's possible we may have missed something, but we are pretty confident we've got it sorted. We're putting extra people on board on the night to make sure, and we also have people involved in 11 early-warning sites worldwide who will keep our websites updated hourly on what is happening elsewhere as the new year rolls in," Mr Murray says.
The State's electricity generation systems are understood to be fully compliant following extensive testing and upgrading over a three-year period. Some ESB systems have been rolled forward, and are operating in 2000 already.
According to Mr Gerry Condon, ESB's Y2K programme manager, the estimated millennium power load will be about 2,700 megawatts, well short of the ESB's 4,400 megawatt capacity.
"We are confident all our critical and key systems are Y2K-ready. Because of the nature of the power system guarantees are not possible, but in relation to the Y2K work that's been done, we're offering a high level of assurance to customers," Mr Condon says.
On the aviation front, the prospect of aircraft falling from the sky is unlikely within Irish airspace at least. The Irish Aviation Authority, which holds responsibility for air-traffic control, has had its Y2K project in place since mid-1998.
The latest update, published in October, showed the project to be almost complete, and the air-ground radio system, radar and aircraft airworthiness systems had been deemed compliant.
Aer Rianta, which takes care of on-the-ground airport management, recently issued a statement saying it "expects business as usual before, during and after the millennium rollover".
Water provision, a key and often underrated utility, has also been addressed. Dublin Corporation has spent more than £1 million in the last 18 months implementing a Y2K strategy. The telemetry system, which manages the distribution of water throughout the city, has been replaced, and at the production works, back-up generators are in place to ensure uninterrupted service.
According to Mr Michael Phillips, Dublin Corporation's chief city engineer, the sewage treatment process will flow normally but at reduced rates if the pumps were to break down.
"The private sector doesn't appreciate we have standard procedures in place for storms and floods etc. Y2K is a particular problem, but we have a lot of back-up resources in place we can divert to the Y2K problem." Mr Phillips predicts the most likely impact of the changeover will be on corporation billing and metering processes.
Dublin Corporation has also spent £750,000 upgrading the traffic-signalling system. Local control devices attached to traffic lights which adapt automatically to volumes passing through, have been programmed to react to any Y2K glitch by automatically reverting to a fixed sequence setting, where the lights change at timed intervals.
The banking sector has probably spent more money preparing against the Y2K bug over the last three years than any other industry. There is now industry-wide confidence payment systems, clearing cycles and inter-operability with other banks have been satisfied.
Mr Felix O'Regan of the Irish Bankers Federation says: "From our point of view, and a plethora of committees that have been operational, Ireland was one of the first countries in Europe to get a green rating indicating we were well prepared in the banking sector."
A spokesman for the Central Bank said it would be monitoring closely the millennium changeover and feeding updates to the European Central Bank and the Bank of International Settlements in Basle. However, it said it was confident the banks had taken all necessary action to become compliant.
Despite early predictions of trains being derailed as a result of the millennium bug, CIE says 18 months of planning has given it a "clean bill of health" for the changeover.
According to Mr Barry Kenny, a spokesman for Iarnrod Eireann: "We have full contingency plans organised, but are confident all systems have been checked and are all clear. We'll even have the DART running before and after midnight right up to 1 a.m."