NATO defense ministers opened talks here today against a background of growing European unhappiness about what they consider U.S. dominance of the alliance's arms purchases.

A new generation of "emerging technology" weapons has sharpened the debate over weapons procurement, with the Europeans saying a strategy focusing on the new, nonnuclear weapons would only widen the imbalance in procurement.

Many of those who now favor a major push toward "emerging technology weapons," with their increased accuracy and destructiveness, say they could reduce defense costs and render less likely the use of nuclear arms. Those two accomplishments would go a long way toward reducing NATO's two thorniest problems in Europe: the unwillingness of member countries to spend as much on defense as the United States says is necessary, and the growing popular movement against nuclear weapons.

But military officials here, including U.S. Defense Secretary Caspar W. Weinberger, have cast doubt on both assumptions.

And some European officials here "smell a rat," in the words of one, since they believe enthusiasm for high technology could worsen what they see as an already unfair American dominance of the NATO arms market. The 12 European defense ministers meeting here yesterday delivered one of their harshest attacks ever against that perceived imbalance, with Dutch minister Jacob de Ruiter calling for "profit sharing as well as burden sharing."

The NATO allies agree in principle on the importance of exploiting new technology for military use. Weinberger said in an interview this week that such weapons take advantage of the West's "strong suit," its lead over the Soviet Union in research, and could produce "ultimately a far better defense."

"But it doesn't substitute for a large number of people, and it doesn't eliminate the present mix of weapons or anything of that kind," Weinberger said, meaning that nuclear weapons would continue to be an important part of NATO's defense.

Weinberger also disputed the contention that high-technology weapons, which account for an increasingly large proportion of U.S military spending, will be cheaper than nuclear or conventional weapons.

"To get the idea that you could do all this and get a better defense for less money is not really correct," he continued. "It's also a fair amount of time downstream, so you're not giving up anything, shouldn't give up anything now."

Among the new "emerging technology" weapons are precision missiles that hit tanks on the move and bomb clusters that can explode after burrowing under airport runways, making them unusable.

NATO officials believe that supersmart missiles and other weapons can help compensate for Soviet numerical advantages in tanks and men. Such weapons could hit behind enemy lines, the argument goes, striking with enough accuracy to destroy protected missile sites, communications centers and other installations now targeted by nuclear weapons. NATO could then stop the first wave of an attack on the ground and stop an incursion without nuclear arms.

The same experts acknowledge that high-tech wars will be susceptible to the same arms-race pressures as nuclear weapons, despite the current western lead in technology.

The new systems include measures to scramble an enemy's communications system electronically and to resist enemy attempts to do the same. More accurate antitank missiles, a top NATO admiral said today, will lead to the development of more indestructible tanks.

Each round, the officials say, will be expensive. A recent report by retired general Andrew J. Goodpaster, former commander-in-chief of the U.S. forces in Europe, and others said NATO countries would have to increase defense spending targets from 3 percent of the gross national product each to year to 4 percent in order to develop high-technology weapons.

But half of the 14 NATO countries are not reaching even the 3 percent goal, according to Adm. Robert H. Falls, the Canadian chairman of NATO's military committee, and today's meeting revealed other financial cracks in the alliance.

In one closed session, the Belgians announced they would withdraw half the antiaircraft missiles they now operate in West Germany, leading the Germans to ask angrily who would take up the slack. The Italians said they would not increase their spending goals to accommodate a high-technology strategy.

All of the Europeans said the Americans must help change what they say is a 15-to-1 advantage in American arms sales to the alliance. Weinberger said in a private session, according to several officials, that he recognizes there are centers of technological research on both sides of the Atlantic.

But several Europeans said they still fear the emerging technology race will only aggravate what their communique called the "present unsatisfactory imbalance," which they say makes it more difficult to persuade their parliaments to increase defense spending. If and when high technology advances, said Canada's chief of staff, Gen. Ramsay Withers, the Canadians will "push like hell" to get some of the action.