NEW DELHI -- Tens of thousands of South Asians look westward to the Middle East and North Africa every year for the basic survival that eludes them in their desperately poor homelands. Whether they be cooks or carpenters, doctors or doormen, engineers or electricians, they go west, to the modern El Dorado of black gold.

Western oil companies, defense contractors and engineering giants flocked to the Middle East and North Africa when soaring oil prices in the 1970s created enormous wealth, and brought with them enormous opportunities. South Asians followed, offering to do anything for these societies starved for manpower, from sweeping streets to manning hospitals, banks and armies.

For the host countries, these foreign workers have become an essential glue to their societies, providing the common skilled labor that their own small populations cannot generate.

In some of the smaller countries, foreign workers outnumber natives by as much as 10 to 1, a ratio so startling that census figures almost become vital national secrets. This has raised questions of whether or how these countries could survive in the event of an exodus by their imported labor.

In some of the gulf states, especially those with large numbers of foreign workers who either come from other Arab nations or are stateless Palestinians, the imbalance has created a security fear: what would happen if the non-native workers become disenchanted or fall under the influence of governments hostile to their hosts?

The recent decline in oil prices has put a crimp in the gulf job market, causing economic problems in countries that became accustomed to the millions, even billions, of dollars flowing home every year in remittances from workers abroad.

Nevertheless, the lure of the gulf remains strong for their job-hungry millions.

Vijay Pal, a cook in New Delhi, went to Dubai two years ago. His salary, about $400 a month, plus housing and a round-trip air ticket, was five times what he could make in the Indian capital, if he could find a job at all. He saved enough to buy a motor scooter and other consumer items that a novice cook could never dream of purchasing on his Indian salary. Wages that are three to five times more than South Asian salaries are normal in the gulf.

In Dubai, a Bangladeshi who has not lived in his country in years speaks proudly of the apartments costing tens of thousands of dollars that he has bought for his son and daughter, who now live in Karachi.

An Indian white-collar worker recently purchased a Mercedes-Benz and says he is now saving for the massive customs duties that he will be required to pay when he takes the car home.

Another Indian, a truck driver, glows when he talks of the good marriages that he has arranged for two daughters because of the high dowries that he paid with his gulf earnings.

In 1985, according to a recent International Labor Organization study, there were 4.3 million migrant laborers in Saudi Arabia, the United Arab Emirates, Kuwait, Qatar and Oman, and the majority of them are from South Asia.

The influence of the gulf can be seen throughout the vast South Asian region: Long lines at airport customs counters are common as Indians, Sri Lankans, Pakistanis and Bangladeshis bring home consumer goods purchased with their newfound wealth. Portable stereos, video cassette recorders, refrigerators and washing machines pour out of the bellies of 747s that arrive daily from the gulf.

In Kerala, in southern India, land prices rise and fall with the numbers who head off to work in Dubai, Libya or Saudi Arabia and with the salaries that they are paid. A measure of the Kerala-Dubai nexus is the the number of flights that Air India operates from the small airport at Trivandrum to the United Arab Emirates sheikdom -- nine a week.

In Pakistan, central planners fearfully watch remittances from the gulf. They stood at about $2.5 billion in the early part of the decade, but may not reach half that amount this year. In 1985, the 986,000 Pakistanis in the gulf countries sent home an amount officially estimated at $1.9 billion. Remittances from all sources are expected to fall short of that amount this year. The falloff in remittances undercuts Pakistan's balance of payments position.

In New Delhi, Labor Minister P.A. Sangma told Parliament recently that an estimated 926,000 Indians were working in the gulf. About 53,000 left during the first six months of this year, he said, down from 58,000 in the same period last year. Reflecting reports from elsewhere, he said there has been a shift in the types of jobs being filled. Skilled job seekers make up 70 percent of those going abroad. Formerly, unskilled workers predominated.

There has been a down side to the lure of jobs or quick wealth in the gulf. Families are separated for months, sometimes years, and prospective workers are gouged by unscrupulous employment agents, despite licensing procedures and regulation. Many of the workers often are charged large fees for their jobs and visas and have to borrow money at exorbitant rates to pay them. Loss of a full year's salary is not uncommon.

For women, more than money can be involved. Sexual exploitation is said to be common. A local journalist in Dubai recently related the story of a young Indian woman from Hyderabad who married a young Dubai man in India. As soon as he brought his new bride to Dubai, he divorced her and told her to marry When South Asian workers in the gulf go home with increased expectations, they find that there are no jobs available, or only jobs at lower pay. Soon their meager monetary savings are exhausted.

his aged father. Penniless, she had little choice.

Gulf employment has affected not just the lives of millions of South Asians. The character of life in the small sheikdoms and large Arab states where they work also has changed.

A walk down the streets of Dubai is a walk through South Asia in miniature. Radio stations broadcast in Hindustani -- the mix of Hindi and Urdu that is common to northern India and Pakistan. The tongue-twisting sounds of the south Indian languages of Malayalam and Tamil or the Sinhalese of Sri Lanka waft out of music stores. There are New Delhi laundries. Movie houses advertise the latest hits from Bombay.

Despite a halt in construction brought on by the decline in oil prices, there are an estimated 180,000 Indians and Pakistanis among Dubai's 400,000 people. In the United Arab Emirates as a whole, there are an estimated 500,000 to 600,000 Indians and Pakistanis, well over half the population.

How much of the foreign workers' money has found its way back to families and banks at home is an elusive figure. Much of it goes through a shadowy underground banking system. Conservative estimates for India and Pakistan say 30 percent of money that flows in and out of the country goes through the underground. The actual figure probably is higher.

For countries such as Pakistan and Sri Lanka, even the official remittances, as they are termed, have been a blessing. In broader terms, the oil boom paved the way for a massive redistribution of money, taking it from the western developed world and funneling, through jobs, at least a few of the billions of dollars to the poor of South Asia.

But this flow of money is slowing -- at least for Pakistan -- as the boom in the gulf fades. According to a recent International Labor Organization study, Pakistani remittances from the Middle East and North Africa went from $1.09 billion in 1979 to a high of $2.4 billion in 1983 and have dropped sharply to $1.3 billion for 1986.

Similar figures for India and Sri Lanka do not show such a precipitous decline. Private remittances in Sri Lanka, mostly from the Middle East, stood only at $9 million in 1975 and have risen steadily to $324 million in 1986.

For India, figures are much less certain. Remittances from the Middle East and North Africa rose to the $2 billion level in 1980 and then began to decline slightly. No figures are available since 1984. General remittances, however, including those from the United States and Britain, appear to have remained steady at $2.6 billion.

"Compared to five years ago, the numbers undoubtedly are down a bit," said one expert in the United Arab Emirates. "The biggest construction projects are done, and construction workers are being replaced by service people. They also are getting rid of high-cost westerners and are replacing them with lower-cost South Asians." Increased competition for the available jobs, combined with lower oil income, also has forced down wages, up to 50 percent for lower-level jobs and 25 percent for higher levels, the expert said.

In Kerala, which, according to one recent survey, is believed to supply 70 percent of India's workers in the gulf, officials believe that the decline in jobs is small but the skill level is increasing as operating and maintenance personnel replace construction workers.

The same officials believe that there also is a shift in what workers from Kerala are doing with their money. Earlier, workers would put their earnings into consumer goods or into housing and land. One official reported that during an inspection trip to Dubai, he found six manual laborers living in one room that had six television sets, six radios and six cassette players. These were the workers' "savings."

When these people go home with increased expectations, they find that there are no jobs available, or only jobs at lower pay. Soon their meager monetary savings are exhausted, and expensive-to-maintain houses are sold at lower prices or divided up for rentals.

Now officials see a different pattern at work. More skilled workers are putting more money into long-term savings, even if the amounts earned are less than a comparable job a few years ago.