The money-makers at Fortress Euro in Sandyford, Dublin, are addicted to security. There's triple-fencing, doors with traffic lights and a helicopter-proof roof. From the watchtower and from cameras, all is observed and all recorded.

Just days before euro notes and coin are introduced, most of the preparatory work at the Central Bank currency centre has already been done. Yet with the Army and Garda on standby outside, there's no doubting the vast scale of the changeover operation.

The complex of low brown buildings is enclosed like a prison. All movement is monitored α la 1984 and the atmosphere is quiet. Everyone knows everyone and what everyone does. For staff, access to buildings is granted on a need-to-go basis only.

Inside, the cash-stash is what gangsters, Lotto losers and euro wonks count in their sleep. Whether spent, saved or squandered, it is the stuff of dreams.

With euros stacked on work benches and stored on pallets in padlocked strong-rooms and underground vaults, the place is an emporium of temptation. There's no end to the goodies. But like Eden, alas, the fruit is forbidden. Strictly.

Amid the hum of machinery and smell of ink, the production process seems distinctly industrial. Quantities are on a grand scale and when cash is counted or weighed, the process is repeated several times as a check.

Yacht-sized printers produce 10,000 sheets of banknotes per hour and minting machines make 850 coins each minute, delivering them with a clink-clink-clink rattle in the style of an extremely generous one-armed bandit.

The euro hits the streets on New Year's Day, the morning after the currency before. Still, after a decade's planning, the six-week changeover period represents only one phase in a lengthy process for the Central Bank. Described by the bank's European mothership in Frankfurt as an "unprecedented logistical challenge", the changeover will also be stark and testing for consumers.

But the Central Bank has been in that mode since well before the exchange rates of the 12 euro-zone members were locked in 1999. If the currency's poor performance against the dollar has been the subject of intense interest by economists, speculators and sterling fiends in Britain, attention now is focused on the roll-out of notes and coin.

Suffice to say that this has been the major preoccupation for years at the Sandyford centre, where 40 extra staff have been hired in addition the usual team of 210. The minting of euro coin began in September 1999, while note production started in June last year.

All told, about a billion coins and nearly 300 million notes are required. Most have already been made on machinery introduced as part of a three-year, £35 million (€44.44 million) programme that began in 1996.

This has enabled sophisticated counter-forgery protections to be built into the currency, and the incorporation of up to 100 colours onto banknotes. The paper is supplied with watermark and thread intact and is subject to six printing processes, including an engraving method known as Intaglio.

The currency was designed by Mr Robert Kalina of the Austrian Central Bank, whose plans were chosen after an international competition. Not all of Mr Kalina's work is visible to the naked eye, and the detail merits examination with a magnifying glass. For example, very small lettering on certain notes appears as lines.

"Getting precisely the same quality across the euro zone was the biggest single problem that we had," says the manager of the centre. Security is the priority, so this man is not named.

In his 50s, he speaks of the changeover operation with the certainty of someone who might have lost sleep to ensure its success. Yes, he says, the European Central Bank monitored the process. And yes, there were frequent visits to Frankfurt.

If the introduction throughout Europe of notes and coins presents huge potential benefits for travellers, business and governments, it also means that counterfeiters will be getting to work. And thieves. For these reasons, a tracking system is in place to detect where suspect notes are passed and whether they form part of a new batch. It is likely too that the new series of notes and coin will be replaced in the medium term, to deter forgers.

Indeed, some observers believe the new currency will replace the US dollar as the unit of international crime, because large sums will be easier to transport. The highest denomination dollar bill is $100 (€110.9), while the highest euro is €500. Still, central bankers point out that much of the "money" circulating in the criminal world is forged. It is also argued that central bankers cannot have a moral say over the use of the money they produce.

Of more importance to them is the necessity to make robust notes, which do not disintegrate after a few transactions. The currency centre manager says the paper is subject to crumple tests, while its resistance to heat and chemicals has been assessed under laboratory conditions.

Notes must also pass a "barkeepers" test for resistance to alcohol and water. This of course has particular importance in Ireland, where drinkers pay for rounds over wet counters in pubs. When coupled with the fact that many Irish people do not use wallets, this shortens the life of banknotes. According to the manager, Irish notes have a one-year lifespan. This contrasts with deutschmark notes, which last three years.

Like its methods, the language of money-production is a mixture of new and old. Expressions such as "ink reservoir", "stillage" and "hologram" are common.

The destruction of used notes has its own language too. Time was when the punts taken out of circulation were burned. Now, for environmental reasons, they are chopped into thousands of pieces and stuck together in packets known as "bricks". About the size of a small building block, they are disposed of in landfill sites. Coin is smelted and recycled.

If the overall sense here is one of cautiousness, the wags in Sandyford tell money yarns with aplomb. One stern tale concerns an unfortunate man with a colour photocopier whose false £20 note was tracked back to his machine. Red-handed.

Another suggests that the brother of an Irish business owner spent a recent weekend locked up in a police cell in Amsterdam after he passed a €5 note as a tip in a restaurant. The gesture was intended as a joke. But a batch of Dutch-made notes had been stolen and the authorities were keen to establish where the Irishman acquired the cash.

So just don't take any chances with the euro. When at the currency centre, don't take anything.