After years and months of preparing for the change-over to the euro, an eerie calm has descended on Europe's financial sector as it prepares for its moment of reckoning.

The publication on December 31 of the irrevocable conversion rates for the 11 currencies taking part will signal the start of 72 hours of frantic activity by banks, brokerages, information vendors and infrastructure providers as they convert systems and accounts in time for the opening of markets on January 4.

All believe they have got their planning right, but few are prepared to wager on a trouble-free birth for the new currency.

``It's a bit of an unknown. You can plan but you can never be sure what will happen,'' said spokesman Euan Sellar for the Society for Worldwide Interbank Financial Telecommunication (SWIFT), whose network carries $2.5 trillion worth of transactions a day.

``We believe we have taken all the steps we can but on the first euro business day there will be4,000 banks and 20 or so settlement systems linked through SWIFT,'' he added.

No one underestimates the mountain of tasks to be accomplished after EU finance ministers make the fixed euro rates known around 1230 GMT. Few if any will be joining the ministers in a glass of celebratory champagne.

First, 1998 books must be balanced, then securities holdings and accounts re-denominated and pending transactions converted into euros and re-entered into systems for processing, while countless checks are made to be sure orders are not rejected.

The task has been complicated by the fact no simple rules will apply.

While all euro zone governments have taken the decision to convert most of their public debt into euros from January 4, not all are following the same methodology.

France and the Netherlands are the only two countries to have chosen to round bonds to the nearest euro, but each is doing this in a different way.

Around the world staff who would normally be on holiday have been drafted in tohelp.

``We expect around the globe we will have more than 2,000 people working on this weekend,'' said senior general manager Volker Burghagen for the euro change-over at Dresdner Bank in Frankfurt.

By January 4, Dresdner alone will have converted some 45,000 accounts, 3,000 bonds and a couple of hundred derivative instruments. ``In 40 years in banking, I have never seen a project of such size and complexity as this one,'' Burghagen said.

``Every single employee will be in or on call. All leave has been cancelled,'' said John Gilchrist head of corporate communications at Cedel, the Luxembourg-based clearing and settlement company, which has some 800 staff. Camp beds and catering facilities have been hired for the duration.

Over the weekend, Cedel expects to re-denominate some 4,000 bonds, a list of which is updated daily on its web site.

``The most important thing is to convert customer and internal accounts into the euro, then dealing rooms, stocks, swaps and futures,'' said Anne Roose, head of ITat the Belgian bank BBL, which will have 500 staff working at its offices in Brussels, London, New York and Singapore.

``We will start on the 31st and, if everything goes okay, hope to have finished by 1 am. On the 2nd and 3rd we will do other jobs and testing,'' she said.

Global news and information provider Reuters expects changes to some 20,000 customer pages containing some 40,000 prices. Interfaces to 20 stock exchange feeds affecting 20,000 equities must be modified.