The European Commission has said it is "extremely satisfied" with the roll out of euro cash, on the first day that most shops and banks have opened their doors to the new single currency.

The most serious glitch of the day came when all of Austria's cash machines broke down briefly due to "a failure of the central computer's memory system", a spokesman said.

European commissioner

It's been a warm welcome despite the cold weather outside

Pedro Solbes

Problems were also reported in Naples, Italy where police intervened to calm angry pensioners forced to queue for hours to collect their pensions.

Overall though, the euro's introduction as a cash currency appeared to be mostly trouble-free.

Spending

Pedro Solbes, EU commissioner for Monetary Affairs, said 90% of all transactions should be taking place in euros within two weeks.

"I'm extremely satisfied with the course of events... it's been a warm welcome, despite the cold weather outside," he said.

Citizens of the 12 eurozone nations were busy spending euro coins and notes, as they went about their normal business after the New Year break.

Commuter experiences

For many people, their first encounter with European single currency cash was buying weekly or monthly train tickets, as they returned to work after the New Year and Christmas holidays.

Germans were subjected to long queues

In France, some ticket offices were stacked high with boxes of coins in rolls, in preparation for handing out change to customers.

And once on the trains, commuters - normally travelling in gloomy silence - cheerily exchanged stories about their first euro experiences.

According to local reports, the Austrian cash machine glitch occurred at 1415 GMT when a central computer was unable to cope with the unusually high volume of withdrawal requests.

But a spokeswoman for cash machine operator Europay International told BBC News Online that Austria's cash machines were working normally again by 1600GMT.

Later, a manager at the company that runs the cash points pointed out that indoor machines worked as normal throughout and insisted that the breakdown was neither linked to the introduction of the euro nor to excessive demand.

Mr Solbes said that 80% of Europe's cash machines had successfully managed to dispense euros.

While the largest financial handover in history has gone smoothly so far, a few teething problems inevitably cropped up.

Traffic jams and queues

Consumers in most eurozone states can use their old currencies for up to two months.

But retailers have been encouraged to provide change in euros - producing various incidents of confusion and delay.

You think everything is half the price, so you tend to want to spend more money

Ernst Welteke Bundesbank president

Many stores have hired extra staff for the first major trading day, but there were still long queues at many tills.

In Frankfurt, bank customers had to queue for between 45 minutes and an hour in order to change their Deutschmarks.

And on the A9 motorway linking France and Spain, traffic jams up to three miles long built up around toll booths as cashiers struggled to give change.

Pockets of trouble

There had been a few isolated cases of retailers showing reluctance to accept euros.

Other grumbles accompanying the changeover involved shopkeepers running out of change, over-zealous forgery detection equipment, unco-operative machines, and some post offices being forced to close in Holland.

Some shops have special euro converters

The authorities had warned shops and consumers to lookout for fake money, believing that counterfeiters will use the current unfamiliarity with the notes to bring forged bills onto the market.

But no cases of counterfeit notes have been reported so far.

In France and Italy, strikes at banks and post offices added to the confusion, although the impact was limited and the strikes later called off.

American praise

The euro was also having an impact on the other side of the Atlantic.

At the busy hub of Newark International Airport, Glenn Altchek said the advent of the euro was "fantastic" for business.

"I do a lot of business in Europe and travelling around the countries that use the euro and it will be a good boon for me that I will not have to exchange money back and forth."

Strengthening in value

Elsewhere the political implications of the euro, the European Union's most ambitious integrationist policy, were being mulled by those changing their cash.

EU leaders believe the launch of the euro notes and coins will strengthen economic and political co-operation across the eurozone.

Euro gains

1.8% rise against sterling 1.4% against US dollar 2% against Japanese yen

It has also led to a higher external value of the currency - although it is still well below its initial value when it was introduced in 1999 in its electronic form.

The relatively trouble-free launch of the euro caused it to strengthen in international currency markets, ending above $0.90 against the US dollar for the first time since 11 September.

And the psychological effects of the changeover may encourage a shopping spree, according to Bundesbank president Ernst Welteke.

"You think everything is half the price, so you tend to want to spend more money," he said.