A leading member of Congress last night called for a United Nations-administered solution to the 22-year-old Cambodian civil war, saying it was the best way to prevent the bloody Khmer Rouge from regaining power there.

At an Institute of Politics forum, Rep. Stephen Solarz (D-NY) said any peace agreement that gave the Khmer Rouge a share of power would only lead to further bloodshed.

"The best solution would be the establishment of a United Nations-supervised administration accompanied by a peacekeeping force," said Solarz who chairs a House subcommittee on Asian and Pacific affairs.

"My fear is that a political solution that included the Khmer Rouge would let Pol Pot subvert the administration from the inside while attacking it from the outside," said Solarz, referring to the dictator who ruled Cambodia in the mid 1970s.

The Khmer Rouge killed about 600,000 Cambodians--one-sixth of the population--during its rule from 1975-78, said Nayan Chanda, senior associate partner of the Carnegie Endowment for International Peace. Vietnam invaded Cambodia in 1978 but has recently withdrawn its troops from the country.

David Lambertson, a State Department official specializing in East Asian and Pacific affairs, said it was U.S. policy to bring about a "comprehensive settlement" of the war by verifing Vietnamese troop withdrawal, eliminating the political power of the Khmer Rouge and letting the Cambodian people determine their future.

"But we have not been able to get around the impasse of transitional arrangements," said Lambertson. "The plan by Rep. Solarz could provide a way around that impasse."

The panelists were unanimous in their opposition to the Khmer Rouge and in their expressed interests in finding ways to keep the group from a return to power.

But several experts said they were skeptical of Western nations' commit- ment to keeping the faction from power.

The "reason we are here tonight is becausepeople are still dying in Cambodia, and if theKhmer Rouge sneak their way into power because theWest considers them as a part of a legitimategovernment, there will be more bloodshed," Chandrasaid.

David Hawk, director of the CambodiaDocumentation Commission, criticized the currentU.S. policy which proposes a peace solutionfounded on power-sharing by the four groupscontending to rule Cambodia.

"Current policy illogically supports a civilwar to support a formula that is supposed to end acivil war," said Hawk. He said any treaty thatincorporates the Khmer Rouge into a transitionalgovernment would allow the group to "be back withguns through the legitimate organs of the state."

U.S. Rep. Chester Atkins (D-Mass) charged thatthe American policy of supporting the Khmer Rougeas the only alternative to the Vietnamese-backedcommunist government in Phnom Penh "will go downas one of the greatest moral travesties ofAmerican action of all time.