It was a battle of wills from the beginning. Innovative changes were pitted against deep seated traditions.

The tenacity of the Mediterranean temperament has apparently triumphed, however.

Thus the time-honored siesta, in which life comes to a virtual standstill between 2 and 5 p.m., has been saved at last temporarily.

Midway through a three-month experiment in which Athens' shops worked a continuous 9 to 5:30 day, the government of Constantine Karamanlis grudgingly has conceded that during the summer heat shops may revert to their split-shift day.

It was, said Loukas Yannopoulos, "a struggle between Eastern mentality and modern efficiency."

But few Athenians seemed willing to give up their traditional ways.

Since the government's new timetable took effect in February, it has provoked a public outcry. Though shops no longer were shuttered at midday, periodic strikes closed them temporarily. More importantly, customers stayed away.

"Most of the opposition comes from the small shopowners," said Yannopoulos, 60, who until recently headed the Federation of Private Employees of Greece. "They feared that they'd have to pay higher wages since there was a one-hour reduction in the working day. They also argued that there'd be no business during the midday hours, and that their greatest turnover was after siesta, between 7 to 8."

But, under the new system, workers have a number of built-in advantages," continued the Socialist union leader, whose federation supported the change. "Their workload has been reduced from 48 to 43 hours per week. They won't have the constant hassle of commuting between Athens and the suburbs four times daily."

Yannopoulos' federation, which oversees the country's two commercial employee unions, lobbied for the new timetable for more than 10 years. Only 2,000 of Athens' 28,000 commercial employees belong to unions, however, and wildcat strikes were inevitable.

More than a protest of working conditions, the outcry is based on the radical change in lifestyle.

Conceived as the answer to summer's stifling heat, the siesta provided a reprieve from responsibility and decision-making. Some psychiatrists believe the break is at least partially responsible for Greece's low hypertension and heart attack rates.

It also sends men securrying to the arms of mistresses, or home for hearty lunch and nap.

"It provides that plateau of understanding," said an Athenian politician. "In a very civilized manner, you can balance your time and affections between mistress and wife."

Although it continues as a way of life for Athenians, conditions have changed.

Shops once were "mom and pop" operations, and the family lived at the back or above the shop. Employees usually were cousins who could walk across town in 10 minutes after their midday nap.

But suburban living and an economic upsurge that has clogged Athens with nearly 1 million cars, making commuting a daily nightmare.

"It's also upset our whole system of digestion," said the hefty Yannopoulos. "We've reached the point of not eating dinner until 11 o'clock at night . . . In December, the height of the winter, there are no excuses of heat prostration. But we sleep away the most productive hours of the day."

"It will just be too tiring," argues Eleni Hadjipaylou, who works in one of Kolonaki's chic boutiques. "And in the summer, without air conditioning, the heat will be unbearable. We'll also have no opportunity to go to the beach."

Working wives are disgrunfled over how they will do their shopping and who will cook and mind the children in a city where relatives still pitch in with household duties.

But when the summer heat ends, working hours will be reappraised. In the long run, change seems inevitable in this country where tradition is slowly being uprooted by progress.