The House Foreign Affairs Committee gave quick and unanimous approval yesterday to a one-year extension of conditions on military aid to El Salvador that are due to expire when the current fiscal year ends at midnight tonight. At the same time, the Kissinger Commission on Central America announced plans to visit the region next month.

On a voice vote, the committee moved to keep alive a requirement that, for aid to continue, the president must certify to Congress every six months that El Salvador has made progress in promoting human rights, instituting land reform and prosecuting the killers of American citizens who have died there.

The "continuing resolution" that will provide a large part of the government with operating money into fiscal 1984 includes aid to El Salvador at an annual rate of $64.8 million.

Rep. Michael D. Barnes (D-Md.), chairman of the Foreign Affairs subcommittee on the Western Hemisphere and sponsor of the one-year extension, said it is necessary "to continue the pressure" for changes in El Salvador.

At the same time, Henry A. Kissinger told a news conference that the bipartisan National Commission on Central America, which he heads, will begin a six-day, six-nation tour of the area Oct. 9 as part of its work toward recommending a long-range U.S. policy for the region.

All 12 commission members, their 10 special advisers and staff people will make the trip together, Kissinger said, starting in Panama and going to Costa Rica, El Salvador, Guatemala, Honduras and Nicaragua, and returning Oct. 16. The idea of going in small groups to stay longer in different countries "foundered on the desire of everybody to go everywhere," he said.

The one-day stops crammed with briefings and meetings will still give the visitors "a flavor of the country, a judgment of the personalities, an opportunity to ask questions," Kissinger said. "We will not become full experts on each country," he added with a smile, "but we may manage it in one or two of them."

At a later news conference, Nicaraguan Ambassador Antonio Jarquin invited commission members to stay on in Managua two to four days more "to understand the country better." He said Nicaraguan leaders would tell Kissinger that present U.S. policy toward them is unjust and dangerous for the entire hemisphere.

Edmundo Jarquin, minister of Nicaragua's International Fund for Reconstruction, accused the United States of a "massive effort" to block Nicaraguan access to international financial help. He said Nicaraguan participation in World Bank and International Monetary Fund meetings here this week disproved the Reagan administration contention that Nicaragua is cutting its ties with the West in favor of the socialist bloc.

Kissinger said the commission would not meet with any guerrilla groups on this trip but could meet with them later.

It will "absolutely not" travel to Cuba or meet with Cuban officials, he said, because that would be "a political action, a foreign policy action, not a fact-finding action." The Cubans, he said, "can send us a message and we will treat it seriously."