Senate Minority Leader Howard H. Baker Jr. (R-Tenn) warned yesterday that Republicans would "regret it for years" if they keep assailing one another over the Panama Canal treaties.

"We really must not cannibalize our party," Baker said on the television interview program "Issues and Answers" (ABC, WJLA). "We're not big enough."

In a letter to Republican National Chairman Bill Brock, eight Republican senators had protested last week that conservative GOPopponents of the treaties were trying to purge Republican members of Congress who disagreed with them in a self-destructive display of "cannibalism."

One of the signers, Sen. Jacob K. Javits (R.N.Y.), reitevated those concerns yesterday on another interview program, "Meet the Press" (NBC, WRC). Javits, who said he thinks the treaties are "desirable" pointed out that there are only 38 Republicans in the Senate.

"The cannibalization of Republicans by Republicans," Javits said, would "extremely unwise."

The dispute over the treaties, which would give control of the canal to Panama by the year 2000, was also a major theme for Sen. Bob Dole (R-Kan.) on "Face the Nation" (CBS, WTOP).

An opponent of the pacts who would "delay the turnover" of the Canal Zone. Dole shrugged off the conditional offer of Panamanian chief of state Omar Torrijos Saturday to step down from power if that would prompt the U.S. Senate to approve the treaties.

"I don't think the treatrics of Torrijos indicating he might step aside would make any differences," Dole said. He said he doubted that the treaties could muster the necessary two-thirds majority in the Senate.

Baker said Torrijos' weekend promises of sweeping improvements in Panama's human rights situation were very "important" and welcome, but continued to avoid taking a stand on the treaties.

"In a word, I've decided not to decide," he said. "I'm going to wait."

Bakersaid, however, that he thought the signers of the letter to Brock - organized by Sen. Charles McC. Mathias Jr. (R-Md.) - were "dead right" to be apprehensive.

If an "intra-party confrontation" develops over the canal treaties, Baker said, "I think we'll regret it for years."

Asked about reports that Baker might wind up leading the fight against the treaties, Javits said that would be "very unfortunate . . . I pray he doesn't do it."

Senate Majority Leader Robert C. Bryd (D.W.Va.),who just completed a four-day tour of the Canal Zone with five Democratic Senate colleagues, also remained uncommitted, but clearly indicated that he is leaning toward approval.

Byrd told reporters on the flight back to Washington Saturday that Torrijos' promises to improve human rights improved the chances for Senate approval, since abuses of those rights in Panama have been a major theme of the treaty opposition.

"Wefeel the dialogue has been an important and progressive step forward," Byrd said of the senatorial fact-finding tour. "I don't see how it can help but improve the atmosphre for ratification in the United States."