President Bush expressed growing concern over the deteriorating economy yesterday amid indications that senior administration officials now fear that a recession cannot be avoided.

Sources said administration officials are discussing ways to try to stimulate the economy that are likely to produce another partisan struggle with the Democrats in Congress.

At a news conference, Bush warned that the nation is "in some tough times now" economically and said he would begin a series of meetings with administration officials and outside advisers to determine what he could do "to soften the blow" on families "or to stimulate economic growth."

Michael J. Boskin, Bush's chief economic adviser, acknowledged the problems yesterday, saying of the economy that "at best it is in a lull" that could last beyond mid-1991. A new administration forecast, due to be completed next week, may show the economy declining in the last three months of the year, he said, but he predicted it would regain momentum once the Persian Gulf crisis is over. {Details on Page F1.}

Bush will meet with his top economic advisers today at Camp David. Those scheduled to attend include Treasury Secretary Nicholas F. Brady, Office of Management and Budget Director Richard G. Darman, Vice President Quayle, White House Chief of Staff John H. Sununu and Boskin.

The concern within the administration reflects fears that the newly enacted deficit-reduction package is no longer adequate to head off a recession.

Bush initiated the budget negotiations earlier this year with the hope that a credible plan would prompt the Federal Reserve and the financial markets to lower interest rates. But the gulf conflict and growing unwillingness of foreign investors to fund the U.S. debt have increased the likelihood of recession, putting new pressure on the administration.

Administration officials are discussing elements of a politically salable package that likely would combine a cut in capital gains taxes with provisions aimed at the middle class.

But in the wake of Tuesday's midterm elections, Bush and congressional Democrats appeared at odds over what to do about the economy.

House Majority Leader Richard A. Gephardt (D-Mo.) charged that although middle-class families are under economic stress, Bush wants to give a tax break to the wealthy. He said Democrats early next year will introduce a surtax on the incomes of millionaires that would be used to to fund tax relief for the middle class.

"More than anything, the Democrats in Congress are going to want to try to get the economy of the country moving, revitalized, going," he said. "The phenomena that is out there that is really most bothersome of all is middle-class treadmill, declining wages, an economic situation moving in the wrong direction for most Americans."

Gephardt said the solution was not cutting capital gains taxes, but enactment of higher taxes on the rich, with the revenue used to provide some relief for the middle class.

"If he {Bush} really intends to veto tax fairness for working families," he said in a statement, "that will inspire the Democratic majority and conscientious Republicans to unite for the first {veto} override of the Bush presidency."

Saying "we're in for a whale of a fight," Bush declared he was girding himself to battle the Democrats over new taxes. "I'm going to hold the line on taxes and fight back all these plans that are coming at me," he said. He added that any new taxes would be enacted "over my dead veto."

"That veto power is there and I'm more determined than ever to use it," Bush said. "I was elected to take this country in a certain direction, and the liberals in the Congress want to take it in another direction."

The president sounded a tone of regret over his broken "no-new-taxes" pledge, which caused deep divisions within the Republican party. "I don't think it was popular . . . . But I think it was the right thing to do," he said. The American people, he added, are not confused about his position on taxes. "I oppose raising taxes. And we have this one compromise, and that just reinforced my view, frankly."

Asked whether he would promise now not to raise taxes, he responded, "Absolutely. But you know, some times you run into some realities. . . . . "

Bush also expressed disappointment over Republican losses in the elections, saying, "I'm not talking victory."