The Kuwaiti government is taking measures to cool off the "stock fever" gripping this oil-wealthy nation where furious trading and huge overnight profits on the "parallel" stock market earlier this year raised fears of a crash involving billions of dollars.

So far, the bubble has not burst. But trading on the Souk Manakh, the name of the unofficial market, has nearly come to a halt. Analysts, meanwhile, are talking about a possible shakedown and "dive" in share prices on both the regular and parallel marts, with the prospect that many small Kuwaiti investors will get hurt.

Reacting sharply to a spate of foreign press reports suggesting the likelihood of a crash, the government has rushed to show its support for the Souk Manakh even while initiating a crackdown on brokers, companies and investors to bring the freewheeling market under control. Kuwait and Bahrain are the two principal financial markets in the strategic Persian Gulf, and the boom here has caused jitters throughout the area.

The Souk Manakh, which in Kuwaiti-Arabic parlance means "a camel parking lot," is only a year old but is thought to be larger now than the official Kuwaiti market, which is rated at the seventh to ninth largest in the world.

The unofficial bourse handles the stock of companies that are registered in other Arab states of the gulf but are traded here free of most of the regulations imposed on the regular market. Until recently, investors on the Souk Manakh were making profits of 100 percent or better in a few weeks and sometimes a few days.

Kuwaitis insist that many of the companies listed on the Souk Manakh are sound, but they also acknowledge that an undetermined number are speculative ventures that have yet to show a penny of profit or even carry out any economic activity. This has not deterred Kuwaitis by the thousands--rich and poor alike--from playing the market with a passion. Investors were paying for the stock with checks dated a year or more in the future, leading to a precarious situation in which billions of dollars are tied up in outstanding debts linked to highly speculative dealings.

Local officials and businessmen have dismissed the adverse publicity about the Souk Manakh as a plot by jealous international bankers to discredit it and thus lure the billions in Kuwaiti funds back to markets in London, Paris and New York.

"It is only a phenomenon like what happened in the United States before," remarked Undersecretary of State Rashid Rashid. "Have you forgotten the gold rush and your imaginary mining companies?"

But he denied that Souk Manakh companies were "imaginary," arguing that they had at least their initial paid-in capital and the potential for enormous growth. "Go to Manhattan, and you will touch some of the buildings these companies own over there," he added.

Concern about a possible stock crash affecting the entire nation was the apparent reason that Kuwaiti Crown Prince and Prime Minister Saad Abdullah Sabah toured both the official stock exchange and the Souk Manakh in early April, afterward declaring his full confidence in both markets.

But the government quietly has taken a number of steps to apply the brakes on speculative trading:

* The Ministry of Commerce has told all gulf companies that they must present reports on their activities to their annual shareholders' meetings. Previously, few did.

* The highly respected Finance Minister Abdul Latif Hamad warned the horde of new companies springing up here that using their starting capital for speculation is "clearly against the law."

* The government has refused to allow several new investment companies to go into operation.

* A government committee has been set up to study the gulf companies.

* The government has ordered banks not to lend new money to investors trying to meet obligations on the first forward-dated checks now coming due.

Independent market analysts here estimate that more than $10 billion in such checks wait to be paid off this year. But they report that private deals are being made between debtors and creditors to avoid losses in some cases and estimate that the "net" amount due on all checks may be only $1 billion to $3 billion.

This, they feel, may help to avert a full-scale crash and lead instead to a gradual shrinking of the stock market bubble as the government moves to take control over the Souk Manakh.

Kuwaiti investors give a variety of reasons for the current slump in activity on the Souk Manakh even while insisting no crash is likely. These include the adverse publicity, fears due to the Iranian-Iraqi war, the consolidation of the market after a rapid rise and a slowdown during the current Moslem holiday period of Ramadan.

"Definitely, I don't believe it is going to collapse," said Sabah Rayes, chairman of Gulf Investment Co., one of the oldest and most solid companies on Souk Manakh, owning choice real estate in Manhattan and Paris.

But, he added, "It is going to be shaken down now . . . . It's abnormal to see a market always moving up. It's even against the law of gravity."