Coils of hashish and large blocks of opium regularly are found sitting next to color television sets, tape recorders and homemade weapons on the shelves of the underground smugglers' bazaar of this Northwest Frontier village.

But now something new and more deadly has been added to the bazaar's wares -- "brown sugar," an opium derivative close to heroin, and crystalline white heroin itself.

They are being produced in at least 15 primitive labratories that narcotics investigators say have opened recently in the wildly ungovernable tribal belt that stretches along Pakistan's northwestern border with Afghanistan and Iran. These three countries form the Golden Crescent that is replacing the Golden Triangle of Southeast Asia as the source of most of the West's heroin.

The introduction of laboratories in the tribal belt increases the value of the opium in the region and makes it easier to smuggle to Western markets. They operate free of Pakistani police controls, since the government has no real authority beyond the major roads.

Drug-trafficking in Pakistan came to public attention internationally during the recent hijacking of a Pakistan International Airlines plans flying to Peshawar, the capital of the Northwest Frontier Province. An American who was among the hostages is under indictment on a U.S. drug-trafficking charge and another man on the plane is believed to have been traveling with a false U.S. passport, according to the State Department.

Anti-narcotics agents in Pakistan's capital, Islamabad, say growing numbers of Pakistanis have been arrested during the past six months trying to smuggle heroin into Europe and the United States.

"Basically," said one, "we are seeing Pakistanis do what Iranians had done for years before they were banned from traveling to America and many European countries."

The chance for high profits has been increased greatly by the introduction of the simple laboratories to process sticky, smelly opium into morphine or heroin.

Ten kilograms (22 pounds) of opium sell for about $700 here, officials say. But at the cost of about $1,000 for chemicals, that l0 kilograms of opium can be processed into one kilogram of heroin that sells here for $6,000 to $10,000.

This heroin can be sold for $40,000 to $60,000 in Europe and about $175,000 to $200,000 in the United States. Diluted and repackaged, that kilo retails for as much as $2 million to $3 million on streets of Washington or New York.

"During the days of the French Connection they needed to smuggle large quantities to make a lot of money. Now the markup is so great between the purchase in Pakistan and the sale in New York that all a smuggler needs is one or two kilos, which is easily hidden," said a drug-law enforcement expert.

While the heroin produced by the laboratories in this tribal area is not as refined as what came from the Marseilles labs in the days of the French Connection, it is considered much stronger than Mexican heroin.

Some of it is not water-soluble, according to a narcotics expert here, so it has to be smoked instead of injected. But the laboratories here are getting better, and are producing a stronger and purer heroin.

The Golden Crescent heroin has already flooded Western Europe where hard-drug use is now a major problem in West Germany and Italy, and has spread to the United States, where it is being seen on the streets of New York and Washington.

About 1.7 tons of the 4 tons of the heroin smuggled into the United States last year came from Iran, Afghanistan or Pakistan, drug officials estimate. The Golden Triangle -- a region of Burma, Laos and Thailand -- contributed 1.3 tons and Mexico one ton, they say.

The flood of narcotics from this area started moving into Europe after the record crop of 1979 when Pakistan, Afghanistan and Iran together produced 1,600 tons of opium, more than the harvest in Southeast Asia, when was hit by drought.

Last year's crop in Pakistan, however, dropped to 125 tons, foreign drug experts say, far less than the 800 tons harvested in 1979. All signs are that this year's crop, to be harvested next month, will also be low.

President Mohammed Zia ul-Haq's martial-law government seeks to take credit for the downturn in production, but outside experts indicate it is more likely due to a glut on the market from the record 1979 crop.

The market was so saturated that the price fell from a record $200 per kilogram in 1978 to between $30 and $70 a kilo in 1979.

"At times hashish sells for more than opium in the markets," said one trader. Hashish is a drug derived from the flower of hemp.

Growers are said to have stockpiled their opium to wait for prices to rise. Experts estimate there is more than 350 tons of opium stockpiled in this area, where the drug trade is considered a simple business proposition.

"They don't understand that the poppies they produce cause great problems in the United States and Europe," said one anti-narcotics official.

In the underground market here, just five miles from the Afghan border, traders offer hashish, opium or heroin as openly as smuggled Western appliances.

The problem for the buyer of drugs is getting them past Pakistani customs inspectors who patrol the roads leading from here.