The Senate Foreign Relations Committee has suspended further action on the administration's high-priority security-assistance bill until the Defense Department gives in to a lawmaker's demand for access to a six-month-old report on the military needs of El Salvador.

The committee took the decision after the failure of a lengthy effort by Sen. Edward Zorinsky (D-Neb.) to see the report by Brig. Gen. Frederick F. Woerner last November on the long-range U.S. assistance required for a Salvadoran government victory over rebel forces.

Woerner headed a seven-member military team that spent eight weeks on the study in close cooperation with the Salvadoran military.

Zorinsky said he heard of the report from the General Accounting Office, which also was denied access to it. Zorinsky said he is determined to see the study because he believes that ultimately he will be called on to vote the money to back up its recommendations.

After Zorinsky's initial requests were denied by the Pentagon, Chairman Charles H. Percy (R-Ill.) demanded access on behalf of the full committee, citing a provision of law requiring access to military requirements surveys.

Undersecretary of Defense Fred C. Ikle, who has been handling the matter for the Pentagon, called the controversy "a tempest in a teapot," and said that the Woerner report involves military options in El Salvador that have been "long overtaken by events."

Ikle said the reluctance of the Pentagon to produce the document was primarily because it resulted from a joint study with the Salvadoran military. It is "a matter of principle," according to Ikle, that confidential information supplied by the Salvadorans should be tightly controlled within the executive branch.

Several days ago, in an attempt at compromise, Ikle offered to bring a copy of the report to Zorinsky's office and stand by while the senator alone inspects the document. Zorinsky rejected those conditions, however.

A congressional source who asked not to be identified said there appear to be two reports: one in Spanish that was written for, and partly by, the Salvadorans, and an English-language version for high administration policy makers, which has been closely held at the Pentagon. It is the latter report that Zorinsky, and now other members of the Foreign Relations Committee, wants to see.

The controversy over the little-known document caused the committee to postpone mark-up deliberations on the security assistance authorization bill last Monday. Under the bill, the administration would be able to spend $4.8 billion on security assistance to foreign nations in fiscal 1983, about $1 billion more than under existing legislation.

Woerner, commander of a U.S. infantry brigade in Panama, is one of the Army's most experienced officers in Latin American military matters.