Although the French government insists that the "teething problems" have been solved, there was no sign of the majority of the 400 employees returning to work at the factory at Pessac, near Bordeaux, yesterday.
The unions complain that the French government, anxious to steal a march on its European Union partners, began work on the new euro coins before technical problems had been ironed out.
They also say that manning levels are insufficient to meet the ambitious production targets.
The early start in making the coins, which are not due to appear in European pockets for another three and a half years, has already proved unfortunate in another respect.
The European Commission halted the production of the 10-cent coin two weeks ago, after pressure-groups for the blind complained that they could not be readily distinguished by touch.
The design will have to be reconsidered and the 9 million coins already minted at Pessac melted down.
Michel Mano, a local official of the CGT trades union federation, said that there had been many technical problems in the rapid changeover to euro coins and the workforce was no longer prepared to carry on without reinforcements. Otherwise, he said, the factory would miss its 1998 targets because the management had "overestimated production capacity".
The managing director of the mint, Francis Reillac, said yesterday that he had already promised to hire an extra 18 people and could not go any further.
Euro coins and notes will become legal tender in the 11 countries joining the single currency on 1 January 2002. For the first six months, they will circulate alongside national currencies, which will disappear from July of that year.
By the end of 2001, the French national mint has been asked to produce 7.6 billion Euro coins, containing enough metal to build four Eiffel Towers.
There is no particular commercial advantage to France in sprinting ahead of other Euro countries in minting the coins. All will make their own versions of the Euro currency, with slight differences to include national symbols.
t Maputo (AP) - The French President, Jacques Chirac, said Africa's former colonial powers and other, Western creditor nations must consider alleviating debt burdens stunting the development of countries such as Mozambique. Mr Chirac, on a tour of southern Africa to promote French interests in the region, said France would press for foreign debt relief.