Indira Gandhi swept her Congress-I Party into an early commanding lead this morning in the Indian general election and in a stunning reversal of political fortunes appeared to be on her way to returning as this country's next prime minister.

Final results in the voting by this country's huge electorate will not be available until Tuesday, but the trend was clear from the earliest results Sunday night: Gandhi's supporters had won or were leading in areas where they were not expected to do well and were holding on to seats they were expected to win.

The heavy pro-Gandhi vote appeared to serve as a vindication of India's only national political figure.

Nearly three years ago, following a period of almost two years of rule by emergency decree, Gandhi and her party were thrown out of office in a humiliating election disaster. The vote was widely viewed as the people's response to the period of emergency rule, which saw tens of thousands jailed, thousands forcibly sterilized, personal liberties curtailed and press censorship imposed.

The excesses of her emergency rule provided the main arguments against her in the long and bitter election campaign that just ended, while Gandhi and her supporters insisted that the Janata coalition that had defeated her in 1977 had led the country to economic ruin, causing a breakdown in law and order.

Inflation, compounded by a disastrous drought that has ravaged crops, undoubtedly turned voters' thoughts away from their problems during Gandhi's last period in power and further undermined a government coalition that had seen its cohesion collapse and its majority slip away as a result of internal squabbling.

In turn, Gandhi, 62, showed incredible stamina as a campaigner, standing in sharp relief to her opponents, whose bumbling ineptitude led one commentatoar to say she was "virtually presented" the country "on a golden platter."

Early today, United News of India gave Gandhi's Congress-I Party 64 seats of the 78 that had been declared won. In addition, Congress-I candidates were reported to be leading in 45 of the other 51 seats where counting started Sunday.

The huge Indian elecorate votes in two stages and the first results came from districts that voted Thursday. Counting started Sunday night for districts that voted Sunday with the final results expected tonight or Tuesday.

"If this holds up it looks as if Congress-I is poised for a sweep -- not just a majority but a sweep in the poll," commented a Western diplomat who keeps a close watch on Indian politics.

"It is very hard to believe this patern will not hold up. It looks as if she will have a majority and will be able to form the next government of India."

Still to be counted today are votes from the states of Uttar Pradesh, Bihar and Rajasthan, which have 164 seats in the 542-member Parliament. Few here this morning expect those votes to upset the Gandhi bandwagon.

Most observers here expected Gandhi's Congress-I Party to win the largest number of seats in the Parliament. But the strength of her victory over the leading contenders, Jagjivan Ram's Janata coalition and Prime Minister Charan Singh's Lok Dal (people's) Party, was stunning. Lok Dal failed to win any of the seats declared so far.

In the state of Orissa, for example, where the Lok Dal was expected to win as many as 12 seats. Congress-I appeared on the way to sweeping all 20. Even Bijaynada Pattanaik, an Orissa political leader for the past 20 years, appeared to be losing by a substantial majority.

Similarly, in the state of Karnatake, where Chief Minister Devraj Urs split from the Congress-I, Gandhi's party won four seats and was ahead by comfortable margins in 10 others.

In Gujarat, where the Janata and Lok Dal were expected to split the vote, Congress-I won all 13 districts being counted. In the Punjab, her party led in 12 of the 13 districts that voted Thursday. Former home minister H. M. Patel was among those defeated.

Her most surprising victories came in Dehli, which rejected Congress-I in 1977 and where the Janata was expected to be strong. But Congress-I cnadidates won five of seven seats, including one in the heavily Moslem area of Old Delhi where Gandhi was believed to be weak because of mass dislocations of long-time residents and forced sterilizations that were part of her emergency rule.

One of the two Janata winners in Delhi, however, was A. B. Vajpayee, former foreign minister in the Janata government, who defeated Congress-I's legislative leader, C. M. Stephen.

Gandhi had campaigned daily from dawn until long into the night, criss-crossing the country in her chartered aircraft. Political observers noted that jeeps, taxis, cars and scooters bearing her party designation were seen at crossroads and tiny villages throughout the country -- an indication both of good organization and plenty of money.

She hammered at bread-and-butter issues, such as the high price of onions and how women's gold bracelets were being snatched from the wrists by bandits in some of Delhi's poshest areas.

With inflation up 20 percent during the past 11 months compared to near zero during the last years of her administration, she was able to blunt the main point of her opponents -- the excesses of her emergency rule.