A long-simmering split in the U.S. Court of Appeals here erupted into a public squabble yesterday, with liberal members of the court accusing their conservative colleagues of deciding cases by majority rule instead of rule of law.

The conservatives countered that the liberals don't know an important case when they see one.

The judges aired their dirty linen in an extraordinary set of public statements published yesterday that were prompted by the court's equally extraordinary action reversing its decisions to grant en banc hearings in four cases.

Cases before the appeals court are normally heard by panels of three judges, but a party may appeal a panel decision by asking for an en banc hearing before all members of the court.

Judge Harry T. Edwards, writing for the liberals, accused conservative members of deciding en banc petitions based on "self-serving and result-oriented criterion" -- that is, simply to reverse three-judge panel opinions written by liberals.

"The implicit view {is} that every time a majority of the judges disagree with a panel decision, they should get rid of it by rehearing the case en banc," Edwards wrote.

The collegiality and dialogue needed for the court to function is being replaced by politicking, Edwards and the liberals said.

The conservative faction, headed by Supreme Court nominee Robert H. Bork, issued an unsigned, joint statement that said three of the cases deserve a hearing by the full court because "each involves an issue of exceptional importance and . . . received a panel resolution that we think is clearly wrong, and is, at the very least, highly dubious."

Judge Kenneth W. Starr, who joined in the conservatives' statement, also issued a separate statement, denouncing the whole thing as unseemly, and declared that the public feud "contributed to a regrettable aura and reality of instability and confusion."

"This is all the more to be lamented in a court blessed with our rich tradition and history, including a heritage of the highest traditions of bench and bar of lively disagreement," Starr added.

Several lawyers who practice before the appeals court here and other court observers said yesterday they were shocked that the court had chosen to bare its internecine battle, and said they could recall no such previous public display.

Neither Edwards nor Bork could be reached for comment yesterday.

Members of the court, which is considered second only to the Supreme Court in power, have been bickering since the conservatives gained the upper hand last summer after decades of liberal rule.

The rift widened in recent months as Reagan-appointed conservatives, led by Bork, voted to review a series of cases decided by three-judge panels with liberal majorities.

In all, the full court had voted since January to hear 11 cases en banc, compared with only three or four such hearings in each of several recent years.

Then, one of the Reagan appointees, Laurence H. Silberman, changed his mind. And because one seat of the 12-member court is vacant, he became an unlikely swing vote who tipped the scales for the underdog liberals.

It's not known exactly when or how it all happened -- en banc votes are taken in private and the tallies are not announced -- but apparently in late June the full court cast new votes on four cases and de-en banced them all.

Voting against full bench hearings of the cases were Silberman, President Carter's appointees Edwards, Chief Judge Patricia M. Wald and Judges Abner J. Mikva and Ruth Bader Ginsburg, and President Johnson's appointee Spottswood W. Robinson III.

Voting in favor of en banc hearings were Judges Bork, Starr, James L. Buckley, Stephen F. Williams and Douglas H. Ginsburg.

Silberman issued his own statement, explaining his reversal, and took a swipe at both liberals and conservatives.

"I am one who, upon reflection, has reconsidered his views and am now inclined to favor en bancs only in cases of exceptional importance to this circuit {emphasis by Silberman}," Silberman wrote.

"Given the increasing number of cases designated for en banc rehearing and the considerable strain those cases place, directly and indirectly, on the functioning of the court, I see nothing unusual or improper in the court's reassessment of its en banc caseload," he said.

Commenting on a case involving Medicare payments for a woman who was treated at a Christian Science facility, Silberman said the majority opinion by Edwards and Senior Judge J. Skelly Wright and the dissent by Bork were like "World War I armies scrambling sideways to the channel, covered a good deal of ground."

"The question will surely eventually be resolved by the Supreme Court and, in the meantime, I doubt very much whether the work of this court will be seriously affected by our refusal to rehear the case," Silberman concluded.

In the Medicare case, the question was whether a claim of $268 could be heard by a District Court -- where jurisdiction is reserved for such cases with claims of at least $1,000 -- if a constitutional challenge is involved. The panel said the case could be considered.

One of the two other cases that now will not be heard en banc centered on the question of what a District Court judge could order having determined before a trial that a prosecutor had added a criminal charge after a person arrested on a misdemeanor count demanded a jury trial.

The District Court judge dismissed all charges against several White House protesters, finding that federal prosecutors had acted vindictively in adding a second charge, and the appeals court upheld the decision.

The other case raised the legal question of how much legal discovery, or fact-finding, a person is allowed in cases seeking damages from individual police officers, who normally would be shielded from such suits, if the person raises a claim that his constitutional rights were violated.

The appeals court allowed some discovery in the case, which stemmed from the disturbance after the November 1982 Ku Klux Klan march in downtown Washington.