White House officials said yesterday that the recommendation of a midlevel group of government officials for a crackdown on leaks of sensitive government information has been placed "on hold" because of internal opposition to the proposals.

Referring to the proposal, which calls for the establishment of a special strike force of FBI agents to probe such disclosures, a senior White House official said, "It certainly will be subject to a lot of modifications if it ever sees the light of day."

The recommendations were contained in a secret memo presented to national security adviser John M. Poindexter last week.

Senior officials said that critical questions about the recommendations had been raised by White House chief of staff Donald T. Regan and Treasury Secretary James A. Baker III, who was described by one administration source as "urging caution" on the plan.

Officials said they also expected objections from Secretary of State George P. Shultz to at least one aspect of the recommendations, an increased use of polygraphs to detect leaks, noting that he has opposed similar proposals in the past.

Whether any recommendations are made to President Reagan for a change in present procedures will be determined by a Cabinet-level group of officials charged with evaluating national security intelligence, officials said. This group may not meet for several days or even weeks because many of its members are traveling. No action will be taken unless the entire group is present, a senior official said.

The group includes Central Intelligence Agency director William J. Casey, a presistent advocate of punitive action to prevent leaks and punish leakers, plus Attorney General Edwin Meese III, Defense Secretary Caspar W. Weinberger, National Security Agency director Lt. Gen. William E. Odom, Poindexter, Regan, Baker and Shultz.

The classified secret memo of the midlevel officials was prepared for the Cabinet-level group, sources said, and delivered to Poindexter. One official familiar with its contents said it included calls for sterner measures against employes who leak classified information, increased use of polygraphs and the creation of the special FBI group.

Several officials compared the proposal for the FBI strike force to the "plumbers unit" that operated in the Nixon White House during the early 1970s. One senior official called the proposals memo "a nonstarter from beginning to end" and said it would provoke complaints from the news media and Congress that the White House was using unconstitutional means to suppress information.

A senior official said that the proposal by the midlevel group was in some respects "remarkably similar" to the recommendation made to President Reagan in 1983 by then-national security adviser William P. Clark, Meese and Casey calling for a Justice Department investigation into leaks and widespread use of polygraphs. That proposal was scrapped by Reagan after opposition led by Baker, then the White House chief of staff, and Shultz.

The present recommendations are "not quite as specific" about the use of polygraphs to ferret out leakers but clearly imply the use of such devices, said one source.

Of particular concern to White House critics was the purported failure of the midlevel group to distinguish between relatively innocuous leaks of information that the administration is withholding for political reasons and genuine national secrets. An administration official said the group did not present evidence of violations to justify the drastic actions it proposed.

"Casey just wants to stop any kind of leaks, anytime, and Poindexter is a military man without any experience in what is permissible disclosure and what is not," said an official. Poindexter is a vice admiral in the Navy who has retained his active duty status while serving as national security adviser.

None of the recommendations have yet been put before Reagan, who in a speech yesterday to veterans of the World War II Office of Strategic Services -- a precursor of the CIA -- praised his former campaign manager Casey as "our leader and good friend and surely one of the heroes of America's fight for freedom in the post-war era."