In the wake of last week's military coup, there were few telephones in the Turkish capital here as busy as that of Turqut Ozal, who was economic adviser to ousted premier Suleyman Demirel.

In the first 24 hours after the coup, family members said later, Ozal received urgent telephone calls from Washington, Tokyo, London, Paris, Bonn, Riyadh, Geneva and dozens of other cities.

Finance ministers, bankers, international lending organizations and economists called Ozal on hearing of the sudden coup to ask how it would affect the draconian economic recovery program to had instituted earlier in the year to stave off national bankruptcy.

International concern was not so much over the plight of Demirel and his democratic government as over what would happen to Ozal and the economic reforms he had tried to impose on the nation.

Although he held no Cabinet position, being only the head of the state planning organization and an undersecretary in the prime minister's office, Ozal was seen internationally as the single most important Turkish offical.

The five-man military junta was also quick to acknowledge his role.

The most important of the first telephone calls to Ozal after the coup came not from abroad but from the generals. Hardly were the tanks in place in the streets than Ozal was summoned to brief the military junta -- which had itself formally sworm in today -- on the economic situation. The junta urged him stay on in his job for the good of the nation.

"The generals had very little choice," said the embassador of a NATO country here. "If Ozal were to quit, they have had it."

It was hardly an easy decision for the junta. Ozal, a corpulent man who fancies tinted glasses, is in many ways the antithesis of the new-wave Turk that the military hopes to see in an eventual civilian government.

Military men are loyal Kemalists, that is, followers of Kemal Ataturk, who founded modern Turkey in 1923 on the ruins of Ottoman Empire. Not only does "Kemalism" dictate a rigid secularism, separating Turkey's Moslem religion from the state and its government, but it also denotes a rifd protectionist state economy that shuns reliance on foreigners for the sake of economic independence.

Ozal is a devout Moslem who prays daily, fasts during Ramadan and makes pilgrimages to Mecca. He is also determined advocate of the free-market economy, which would open protectionist barriers to international competition, tying the national economy to that of its European and NATO allies.

The generals also can hardly take much joy in the fact that Ozal, aside from being a crony of Demirel since their student days in Istanbul, is also a sometime follower of Necmettin Erbakan's Islamic revivalist National Salvation Party on whose ticket he unsuccessfully sought a seat in parliament in 1973.

Demirel and Erbakan are among political leaders under "protective detention" by the military and are despised by the generals and blamed for allowing the country to deteriorate to near civil war because of their politicking. A communique issued today said 50 political figures are still detained and some are being prosecuted.

Ozal's power, however, is that he commands widespread respect abroad among the foreign governments and lending institutions upon which Turkey's economic survival depends today. His prestige goes back at least to the early 1970s when he served for three years with the World Bank.

Ozal instituted the current economic policies so respected abroad in January, shortly after being brought into government by Demirel.

The generals have been at pains to emphasize -- in communiques, press statements and private briefings to foreign ambassadors here -- their intention to adhere to Ozal's recovery plans.

Ozal's draconian measures devalued the Turkish lira by more than 100 percent this year, let prices rise to their natural level after the lifting of state subsidies on unproductive national industries, and removed restraints on foreign investments.

As a result, Ozal managed to negotiate $1.6 billion in assistance from the International Monetary Fund and another $2 billion in aid over the next two years from the Organization for Economic Cooperation and Development.

Those two expressions of international confidence triggered further aid, including the rescheduling in July of more than $2 billion in payments due on the staggering $16 billion national debt. A smattering of important loans came from such nations as Saudi Arabia.

Given the fact that last winter Turkey could not pay for needed fuel, those loans could represent the difference between Turkey's collapse or continued survival.

The generals know that for Turkey to become a viable democracy, they not only must end extremist violence but also deal with the social and economic crisis that spawned it. For that, Ozal and his moneyed foreign friends are vital.

So important is Ozal's continued power over the economy viewed here that in some circles he has been touted as a possible premier or finance minister when the military get around to announcing a civilian cabinet to administer the country under their direction.

Other observers doubt that Ozal will emerge in such a visible position. It is more likely they maintain, that he will keep his present posts and, as the economic czar, oversee all of the ministeries involved in the economy.