United Auto Workers President Douglas A. Fraser today reported "significant progress" in final-stretch contract negotiations with General Motors Corp. and said he is "guardedly optimistic" that a strike against the giant automaker can be avoided.

With less than 24 hours to go before the Friday midnight strike deadline, GM negotiators submitted a new economic package to the union early in the evening. There was no announcement of the latest terms, nor public reaction from the union, as the two sides bargained late into the night.

At a press briefing earlier in the day, Fraser indicated that, if the company's new offer on wages, pensions and time off was in line with its stance on some already settled noneconomic issues, the UAW might be able to get a new three-year auto industry contract without a strike against its target company for the first time since 1964.

"Logic dictates to us that we would not have been able to settle these enormously complex non-economic issues with the company if it was not going to try, in the closing hours, to resolve the economic issues," said Fraser.

"It would be a shame to let it get away from us now," he added, noting that the next few hours will be "very, very sensitive."

Neither Fraser nor corporate bargainers were willing to predict a strike-free settlement, but sources from both sides said the general atmosphere and progress thus far have been unusual if not unprecedented in their relations.

In another sign of progress, the company and the union reported that 37 or 38 of 151 local contracts have been completed, compared to the usual seven or eight at this stage of bargaining.

The last time General Motors was the target company for reaching a pattern agreement for the whole industry was 1970, when the union waged a 67 day strike, still the costliest in the nation's history. At the start of the current negotiations two months ago, many economic analysts were predicting a lengthy strike, some forecasting a GM shutdown of up to 75 days.

But GM, eager to establish a solid beachhead for its popular new fuel-efficient front-wheel drive cars, last month signaled its strong desire for a peaceful settlement with an initial money offer that the union hailed as a good foundation for settling without a strike.

It was largely because GM's low inventories for its fastest-selling models made it highly vulnerable to a shut down that the UAW chose the company, the biggest of the Big Three, as its strike target this year.

But at the same time UAW leaders said they would limit any strike action to 46 company facilities employing on 95,000 of its more than 450,000 workers at GM, thereby hitting the corporation where it hurt the most by crippling production of the most popular cars and at the same time slowing the drain on the union's nearly $300 million strike fund.

While pressure is intense on GM to settle without interrupting production, the union feels pressure for a quick settlement, too. The financially troubled Chrysler Corp., which employs 124,000 UAW workers, is hard-pressed to complete its proposal for federal assistance without knowing its future labor costs, which hinge on the out-come of the UAW-GM negotiations. Moreover, the nation's economic slowdown has spawned more than 80,000 layoffs in the auto industry, with more to come.

GM'S first contract offer continued and in some cases expanded the general outlines of the UAW'S current three-year contract with the industry, including 3 percent annual wage increases, cost-of-living protection and one of the best benefit packages of any union in the country. GM workers now earn $15.10 an hour in wages and benefits, including an hourly average wage of more than $9.

The initial offer, made by the Ford Motor Co. as well as GM, appeared to exceed the Carter administration's anti-inflation guideline of 7 percent per year for wage and benefit increases, even though GM had earlier urged industry compliance with the standard. Both sides say the guidelines, now in the process of revision, have not been a factor in the talks here.

Wages are not a principal issue in the negotiations. Bargaining sources say the major unresolved issues involve cost-of-living protection for retirees and more paid days off, which were the union's principal goals at the start of the talks.

GM has rejected the union's demand for tying pensions, now averaging $700 a month after 30 years of work, to the constantly rising wages of active workers but has indicated a willingness to bargain over specific phased-in pension increases the company has proposed increasing the number of paid days-off from 12 to 19 over three years; the union, pushing ultimately for a four-day work week, wants more.

In his press briefing, Fraser said communicatons are good enough to rule out a "strike . . . by miscalculation." But Fraser, a UAW officer for the last 36 years, would not preclude a strike over unresolved contract issues, saying he has been in enough negotiations "to know you can become derailed."

Fraser, joined by Riving Bluestone, head of the union's GM division, said the negotiations will continue through the night as long as progress is being made.

The UAW already has ruled out a contract extension. GM, apparently anticipating a settlement with the UAW in the United States, has agreed to extend its Canadian contracts on a 24-hour basis.