The commitment yesterday by President Bush to include "tax revenue increases" in the budget deficit reduction package being negotiated with Congress increases the odds that federal spending will be cut and taxes raised at a time the U.S. economy is growing very slowly.

Depending on how financial markets and other parts of the economy respond, the restraining effect of tax increases and fewer federal purchases could tip the nation into a recession, a number of economists have warned. A substantial number of them, however, believe reducing the deficit is important enough to run that risk.

When the negotiations began several weeks ago, both the administration and congressional leaders settled on a deficit reduction target of about $50 billion or $55 billion for fiscal 1991 on the grounds that quickly slashing the deficit by a larger amount could endanger continued economic growth.

Most economists believe trimming the budget deficit would lower interest rates because the government would be borrowing less. In the process, more money would be available to private individuals and businesses at a lower cost.

But higher taxes and lower government spending also have the effect of slowing the economy by reducing the amount of goods and services purchased by consumers and government, and some economists now wonder whether this would overwhelm the otherwise salutary effect of lower interest rates on economic growth.

Analysts generally assume that long-term interest rates -- the rates paid by bonds of three years or more -- would fall when financial market participants became convinced the deficit actually would be coming down. Then it would be up to the Federal Reserve to take steps to pump enough new cash into the banking system to bring down short-term rates as well.

But with the gross national product rising at a stagnant 1 percent to 2 percent annual rate, after adjustment for inflation, there is a possibility that even prompt Fed action might not be enough to keep the economy from sagging with a cut in the deficit of $50 billion or more, which would be equal to about 1 percent of GNP.

"You would like to have a clear understanding with the Fed," said economist George Perry of the Brookings Institution. "Do the right thing for long-run budget policy and leave it up to the Fed to do the right thing with interest rates."

But doing the right thing might not be enough in the short-run, Perry continued. "This is the first time in a long time that I have felt the economy is shaky. This is a worse time to {cut the budget deficit} than any in the last five years."

"But I still say do it. I think there is a room for interest rates to fall a lot," Perry declared.

Federal Reserve Chairman Alan Greenspan and other Fed officials have rejected attempts to get them to commit themselves in advance to reduce short-term interest rates if a deficit reduction deal is struck. Greenspan has said that market forces would bring down long-term rates even without Fed action.

Most Fed observers believe, however, that the Fed would move quickly to cut short-term rates. For one thing, the Fed does not want the economy to slip into a recession even though it has raised rates as part of its effort to bring down inflation. If spending cuts and tax increases depressed the economy, central bank officials do not want to be in the position of being blamed for a recession, should even a mild one follow.

Robert Ortner, who until last year was undersecretary of Commerce for economic affairs, agreed that a large deficit reduction package would pose a threat to continued growth, but he would not take such a step.

"The economy does not need a heck of a lot of tightening now," said Ortner, who is the author of a new book, "Voodoo Deficits," in which he argues that the worry about budget and trade deficits has been overdone.

"The economy is already sputtering ... One more twist would do it. Then what have you got? more joblessness ... and what you thought was $50 billion to $60 billion worth of deficit reduction would turn out to be $30 billion" as revenues fell and some spending, such as for unemployment benefits, rose.

Perry and other analysts who favor reducing the deficit believe it would improve the balance between the nation's saving, which has been running at unusually low levels for several years, and its investment needs, which must be financed either from American savings or capital borrowed from abroad. To the extent that the federal budget deficit absorbs a large share of U.S. saving, either investment must be cut back or more foreign capital borrowed.

One key to the response by markets will be whether a $50 billion or $55 billion cut for 1991 would be all there was to the agreement. "If $55 billion is all, it would disappoint me," said Perry. "If it is $55 billion growing to about $110 billion the next year, that would suit me just fine."

Financial markets initially reacted positively yesterday to Bush's statement but the Dow closed off 2.72 points as traders generally took a wait-and-see attitude.