A former resident of Beirut who recently returned whistled in surprise as he drove up the winding road above the ruins of the Palestinian refugee camp at Tal Zaatar.

"This is amazing," he said. "These factories are all working. The last time I was up there there was nothing."

He was passing through the "factory district" in the Beirut suburb of Mkalles. Lebanon's biggest industrial complex, that was devastated in the 52-day siege of the refugee camp in the summer of 1976. When the siege ended, an estimated 20 per cent of the country's industrial capacity lay in ruins.

Fourteen months later, Mkalles is back in business. Half a dozen plants are turning out furniture, hospital equipment, building materials and ice cream. Several others are being repaired and readied for opening - evidance of what appears to be a remarkable resurgence of Lebanese industry after the battering of the civil war.

For months after the Syrian army moved in last November to put an end to the fighting in Beirut, industries showed no signs of any major reconstruction around the devastated city. Some Lebanese returned and opened their shops and restaurants, sweeping out the rubble and installing new glass, but political uncertainty, sporadic violence and the bitter hatreds of war forestalled real economic recovery.There is still a long way to go, but economic experts here say it has at last begun.

Some construction projects abandoned at the start of the war have been resumed. Trucks from Kuwait are again hauling goods from the Beirut port into the Arab hinterland. Bank deposits are reported at an all-time high.

No one minimizes are difficulties still confronting the country. The difficulties were recently compounded by the war in the south that wipped out whole villages, devastated crops and created tens of thousands of new refugees. But at least the entrepreneurial spirit of the Lebanese has begun to show itself again.

"We are now producing at 60 per cent of our prewar industrial capacity," said Mohammed Attalah, chairman of the country's Reconstruction and Development Council. "We see an interest in rebuilding in all sectors."

He and Walid Naja, director general of the Beirut Chamber of Commerce and Industry, said the value of Lebanon's exports already equals the prewar peak, although because of inflation that represents fewer goods. It is, Naja said, "a testimony to the vitality and vigor of the Lebanese."

Lebanon is virtually the only Arab country with a diversified economy based on agricultural and industrial exports. According to Naja, Lebanon's exports account for 70 per cent of all inter-Arab trade and "those exports have not lost their appeal for these Arab markets."

He said the factories of Mkalles, caught in the Tal Zaatar crossfire, were hit harder than other industrial areas, and their destruction was highly publicized, exaggerating the impact on the country as a whole. He said 60 per cent of Lebanon's industrial plants survived the war almost unscathed and are going back to work.

They are reopening gradually as their owners regain confidence and feel ready to invest in them again. The industrial revival is being financed almost entirely with private capital, since the government's resources are committed to reconstruction of ports, roads, public buildings, communications, schools and public transportation.

There has been grumbling from industrialists over the government's refusal to provide them with money or to give loan guarantees that would enable them to borrow on better terms from the cash-rich banks.

Attalah said it is just as well that there is this "tug of war" causing some constraints on reconstructions, because if every industry and public service were suddenly to start operating at once, Lebanon would face an acute labor sortage.

The mass emigration, death and dislocation caused by the war have disrupted the country's labor markets, experts here say, perhaps to the point where reconstruction to the prewar stage will never be possible.

According to recent studies, the supply of unskilled labor was nearly obliterated. The Syrians who provided most of this have fled Lebanon, and the Palestinians who provided the rest were killed or driven off to other parts of the country.

Thousands of skilled laborers and white-collar workers were also among the estimated 700,000 Lebanese who left during the war. But they have continued to send money home, pumping capital into the country, and are expected to return as reconstruction accelerates.

Experts caution that it would be misleading to think that a return to prewar prosperity is in sight. The country's tourist industry, once a mainstay of the economy, is nonexistent. Downtown Beirut and the glamour sports that made the city famous are still in ruins while the government contemplates implementing a French master plan. The task of housing and feeding the masses of refugees remains. But it does seem that recovery is possible if a political formula can be found to forestall a new round of fighting.