Relentless attacks by Sen. Jesse Helms (R-N.C.) on the new U.S- Soviet nuclear arms treaty have prompted an organized counteroffensive from frustrated Democrats, turning the Senate Foreign Relations Committee's deliberations on the pact into hour-by-hour combat for control of the debate.

Since minutes after the hearings opened Monday, Helms has dominated the proceedings with a constant barrage of charges against the Intermediate-Range Nuclear Forces (INF) pact negotiated last month by President Reagan and Soviet leader Mikhail Gorbachev.

While the conservative North Carolinian has been virtually alone in his attacks on the treaty, the sensational nature of some of his charges, coupled with the lack of other fireworks, has enabled him to dominate news stories and enliven otherwise largely uneventful gavel-to-gavel coverage of the hearings on cable television.

Unable to deter Helms and reluctant to leave the charges unanswered, Senate Democratic Whip Alan Cranston (Calif.) got together Tuesday morning with Sens. Joseph R. Biden Jr. (D-Del.) and Paul S. Sarbanes (D-Md.) to organize what a Democratic aide called a "Helms Watch."

"We didn't like to have charges designed to undermine the treaty floating around without a response to them," said Cranston yesterday in explaining the strategy. Democrats wanted to "show we could knock down every argument he made" and "show he's not speaking for all mainstream Republicans," Cranston added.

Helms claimed he is delighted by all the attention. "At least they're talking about our agenda -- the things that give us heartburn," he told reporters after yesterday' session.

Since Tuesday, one or more of the Democrats, all members of the committee, have been close at hand and ready to rebut or ridicule charges within minutes from the moment they are delivered by Helms. Sometimes the Democrats are supported -- even upstaged -- by Republicans such as Sens. Richard G. Lugar (Ind.) and Daniel J. Evans, (Wash.), who support the treaty.

By yesterday, the only witness for the day, senior State Department arms control adviser Paul H. Nitze, became so entwined in the arguments between Helms and his foes that there was little opportunity for substantive questions about verification procedures, even though that issue has been a chief concern of many senators.

The contest also has had its comic moments. At one point, Cranston, informed that Helms was back on the attack, had to dash out of a nearby Intelligence Committee hearing to return to the Foreign Relations chamber to take up sentry duty. Satisfied that Helms was simply reiterating old charges, he said he was "delighted to invite him to the environmental movement" and congratulated him for "recycling arguments."

But Helms said he was nowhere near out of ammunition. "We just got started," he told a reporter, saying he planned next week to launch into questions about how the treaty might constrain strengthening and modernization of NATO forces to compensate for medium- and shorter-range missiles that would be destroyed under the treaty.

In earlier arguments, Helms charged that the treaty favors the Soviets in a variety of ways and provides them with an "engraved invitation to cheat," as he contended the Soviets have done in the past. He has employed arguments normally made by liberals as well as conservatives, including a charge that failure to require destruction of warheads will expand nuclear stockpiles and provide a "trigger for nuclear holocaust."

While Helms' attacks have raised hackles, some INF proponents who have challenged Helms' arguments in committee, such as Sen. Nancy Landon Kassebaum (R-Kan.), have said they have "raised questions that need to be answered and, I think, have been answered," as Kassebaum put it.

Others were less charitable. "It seems to me it's been a total washout," said Lugar about Helms' charges. "By repetition, he hopes to probe for weak spots . . . but I think a strong case has been built against Helms' position," Evans said.

Helms, ranking minority member of the committee, acknowledged he is virtually a lone ranger in fighting the pact in committee, a role he has often used in the past to delay and sometimes defeat propositions that have wide support in the Senate. "I think it's possible if we {Helms} weren't doing it, it wouldn't be done," he said.

Some senators said they thought Helms was seeking mainly to stir up grass-roots opposition among conservatives outside Congress to bring pressure against the INF treaty and future arms-control efforts, including current efforts to negotiate a START agreement to reduce U.S. and Soviet arsenals of long-range nuclear weapons. "I'm looking at this one, and I'm looking ahead," Helms said.

They also said they expected Helms to follow his current campaign with efforts to delay action with amendments, a suggestion that Helms would neither confirm nor deny. "It's a no-lose proposition on my part," said Helms, speaking of his effort.

In yesterday's testimony, Nitze challenged Helms' contention that the Soviets could readily transfer warheads or guidance systems from destroyed SS20 medium-range missiles to long-range missiles not covered by the treaty. "To my mind, it would be wholly unlikely that one could use the explosive package on an SS20 in an SS25," a modern strategic missile, and "impossible" to use the guidance system, Nitze said.

Staff writer R. Jeffrey Smith contributed to this report.