Prime Minister Rajiv Gandhi today invited foreign businessmen to invest in collaborative projects here that could help make India industrially competitive with the developed world in high technology and other areas.

Speaking at a "round table" conference of industrialists from 27 countries, sponsored by the European Management Forum, Gandhi said that foreign investment could help India build a "dynamic, self-reliant" industry without sacrificing the nation's objectives of a mixed economy, equity and social justice.

Gandhi said his government is committed to opening up Indian industry to competitive pressures and "interacting" more with the world market and industry. The goal is not only to overtake other developing countries but also to challenge developed nations, he said.

The prime minister said that India, with a population of 750 million, offers a massive untapped market for consumer items, including electronic goods, and that foreign investment could be used as well in core industries such as energy, communications, agricultural technology and education.

While Gandhi's liberalized industrial policy, which includes removing some licensing requirements and regulations in key sectors and lifting import duties on computers and other electronic equipment, has attracted wide attention here, his speech to the European industrialists was his first major effort to solicit new foreign investment in India directly and on a large scale. He is expected to renew the initiative in June when he makes a state visit to the United States.

Noting that government controls on electronic consumer goods had been revamped, the prime minister said that India is ready to take advantage of its large manpower pool and "good record in dealing with foreign companies" to allow Indian and foreign industry to "work together for mutual benefit."

He dismissed as irrelevant suggestions that India could not compete with Japan and other Far Eastern countries in the market for electronic goods, saying that Indian marketing was not necessarily targeted for export. "We can depend on our own market," Gandhi said, observing that, when import restrictions on color television sets were temporarily lifted for the 1982 Asian Games, Indian consumers overtaxed the supply.

Industry and Company Affairs Minister Veerendra Patil told the same group of businessmen that political stability, economic soundness and prudence in debt management in India offered the best climate for foreign collaboration, and that India would benefit from acquiring sophisticated technology.

"It was in our mutual interests to promote and encourage partnership between Indian and foreign companies so that the economic and technological benefits were shared in a spirit of cooperation," Patil said, reflecting the new prime minister's apparent tilt toward private initiative and entrepreneurship and away from the protectionist and socialist traditions of his mother, Indira Gandhi, and his grandfather, Jawaharlal Nehru.

Gandhi said that, although overpopulation continues to be a major strain on the economy, India is holding to a 5 percent growth rate in national output and that the consumption level of wage-earners has increased. As a result, a large number of Indians have moved above the poverty level and into what he called a "take-off stage" at which increased aspirations would have to be met by industry, technology and government, he told the visiting industrialists.

Last month, the Department of Electronics announced sweeping licensing reforms that will allow manufacturers of "entertainment electronics" to make a wider range of products, including electronic and radio-controlled toys and games, and that will encourage companies regulated by the Foreign Exchange Regulation Act to enter the high-technology field. Moreover, television-receiver production will be thrown open to firms with less than 40 percent foreign equity, and multinationals will be given a bigger role in manufacturing electronic components.

The policy changes are intended to boost electronics production from $1.6 billion to $8 billion in five years and to lower prices of consumer electronics to international levels. Currently, indigenously made electronic consumer goods are prohibitively expensive and often of poor quality.

The moves have prompted considerable controversy in the industrial community, with larger manufacturers welcoming the shift and smaller companies and public-sector industry warning that it could sound their death knell.

Nambi Marthandam, director of Hatari Electronics Pvt. Ltd., a small manufacturer of television sets, complained that the policy had been "drafted by the multinational lobby" and warned that the indigenous small-scale television industry "will be killed by the multinationals." Similarly, R. Venkatraman, president of the Electronic Component Industries Association, complained, "After the Indian components industry has slogged for 20 years, you're handing it on a platter to foreign companies."

The Department of Electronics admits that some small Indian companies will suffer from the policy changes, but officials argue that, in the long run, the failures will be offset by overall technological development.

"Technology was not being upgraded, exports were almost zero, research and development was at a discount . . .true, people will have to undergo adjustments. Some strong companies will emerge and, as a corollary, weak ones will fade out," said S. R. Vijayakar, department secretary.

Government officials and industrialists said that a technology transfer agreement reached between the United States and India last month after three years of negotiations is expected to be a major benefit to India's planned technology boom. The agreement has been hailed as a major breakthrough in U.S.-Indian relations.

Reportedly included in the arrangement are "high-tech parks" to be set up in India, which will receive high-technology data from the United States and distribute it to Indian companies.