Joseph Eldridge was misidentified in an article in yesterday's editions. He is director of the Washington Office on Latin America, a nonprofit research group.

President Reagan plans to announce in Colombia today that he will nominate Lewis A. Tambs, a conservative Latin America scholar, to be ambassador there, according to sources in the diplomatic community.

The Colombians have accepted Tambs, but "they didn't exactly leap on it," one of the sources said, since Tambs, 55, is known for a hard-line anti-communist stance. That is at odds with the well-publicized efforts of the new Colombian president, Belisario Betancur, to reach some kind of accommodation with strong leftist groups there.

Tambs, formerly a history professor at Arizona State University, is now working in the White House as a consultant on Latin America for the National Security Council. He is a protege of Sen. Jesse Helms (R-N.C.), chairman of the Senate Foreign Relations subcommittee on Latin American affairs, who pushed him unsuccessfully earlier for a series of posts in the administration.

Action on the expected nomination could come as early as next week, when the Senate Foreign Relations Committee is scheduled to consider the nominations of two other Latin American ambassadors. Senate staff members predicted a hot debate when Tambs' name is submitted.

Tambs was on the brink last March of being nominated ambassador to Panama, but Panamanians reacted with such anger that the idea was quickly shelved. Tambs had forcefully opposed the treaties relinquishing the Panama Canal both before the Senate approved them in 1978 and during the ratification battle, editing a highly critical report on them for the Reagan transition team.

The authors of that report, "A New Inter-American Policy for the Eighties," which was published by an organization called the Committee of Santa Fe, wrote that Panama had suffered "the left-wing and brutally repressive dictatorship of Omar Torrijos."

That did not sit well in Panama, where the colorful National Guard chief was a national hero and the treaty was a national cause. Torrijos died in a 1981 plane crash.

Tambs' report also warns against "the massive efforts of the Soviet-Cuban axis to subvert from within and attack from without the legitimate governments of this hemisphere," especially Cuban "efforts to radicalize" the coalition of non-aligned Third World countries.

Betancur announced in his inaugural speech that Colombia will join the coalition of non-aligned nations, and boasted Wednesday that his nation "will not be subject to imperialism."

Joseph Eldridge of the Council on Hemispheric Affairs, a nonprofit research group in Washington, said the Tambs nomination would be "a calamity" that will "go over like a lead balloon in Bogota." He said Tambs' "fixation with the communist threat is incompatible with Betancur's more moderate and conciliatory approach, even to the guerrilla movement in his own country."

Tambs declined to discuss his status.