A group of mid-level government officials has recommended in a secret memo to the White House that the administration step up internal investigations into unauthorized disclosures of classified national security information, seeking to find and punish those who release it, administration sources said yesterday.

In a related development, the sources said, a group of top-level government lawyers recently recommended that senior officials take strong disciplinary action against government employes who are discovered to have made unauthorized disclosures. This recommendation resulted in the firing of officials at the Defense and State departments recently.

Both developments appear to be part of an intensifying effort by the Reagan administration to stop unauthorized disclosures of classified information, which has sometimes embarrassed top officials. The sources said a meeting of high-level officials at the White House and other agencies is scheduled soon to take up the issue.

The sources said the moves against government employes who make unauthorized disclosures have come at a time when the administration is in the midst of an internal debate over how strongly to react to news organizations that publish classified information. CIA Director William J. Casey, among others, has raised the prospect of prosecuting news organizations that reveal communications intelligence under a 1950 law never before applied to the press.

A White House official who asked not to be identified by name said there is a "tremendous preoccupation" in the administration with the subject of unauthorized "leaks." The official said the administration is engaged in a "dual-track" effort to combat what it views as a serious problem by trying to discipline its employes as well as persuade news organizations not to publish classified information. But, the official said, "the thrust at the moment is, first we have to clean up our own act."

A second official said some top White House officials, including spokesman Larry Speakes, have argued privately that it would be counterproductive to spend time seeking to prosecute news organizations and that any effort to stem leaks must be directed first at those government employes who disclose the information. However, this official said others in the White House support the Casey effort to attempt prosecution of news organizations.

Sources said the White House memo, which is classified, has been delivered to national security affairs adviser John M. Poindexter. The sources said the memo implied, but did not state, that lie detector tests should be used to identify government officials who leak classified information.

Sources said the impetus for the White House memo was a desire by some officials to come up with a broader policy on leaks in the wake of Casey's recent public statements. One highly placed source said many officials wanted to devise what he called a more "thought out" policy that would consider other options besides warnings to the news media about publishing secrets.

The memo was apparently assembled by an aide to Poindexter, according to sources who have seen it.

The memo was drawn from various mid-level government employes who were asked for recommendations on ways to stem unauthorized disclosures, the sources said. The officials who contributed to the document apparently never met to discuss their recommendations, but their names were included by the official in the National Security Council who assembled their views.

The identity of those who contributed to the memo could not be learned, but the sources said they were generally below the level of assistant secretary and came from various agencies that deal with national security issues, including the State and Defense departments. It also could not be learned who in the National Security Council wrote the document.

Poindexter did not respond to a query through a spokesman about the memo yesterday.

Another administration official said, in response to questions, that "a number of papers have been written" in preparation for the senior-level meeting on the subject of leaks.

"Some but not all of the papers were circulated -- they were meant simply to include some of the ideas that could be discussed at the meeting," the official said.

The official added that "a full spectrum of options" will be considered at the meeting and that no decision has been made.

Although the memo does not specify the use of polygraphs, or lie-detector tests, to carry out internal investigations of government employes, the sources said it has been interpreted in the administration as suggesting their use.

On several previous occasions, the administration has attempted to expand the use of polygraphs, and they are widely used in the intelligence community as a screening device and investigative tool.

In December, Secretary of State George P. Shultz threatened to resign if required to submit to a polygraph examination after President Reagan signed an order requiring thousands of government workers and contractor personnel with access to highly classified information to take routine polygraph tests. At the time, Casey expressed support for the broadened use of polygraphs.

The White House memo was prepared recently following the statements by Casey and others in the administration about prosecuting news organizations. Casey has said he referred to the Justice Department for possible prosecution an NBC News report Monday morning by correspondent James Polk concerning the trial of accused spy Ronald W. Pelton. Casey said Polk's report, "if true," violated the strictures of the 1950 law "against publishing any classified information concerning the communications intelligence activities of the United States." The law has been sparingly invoked against accused spies such as Pelton.

The Central Intelligence Agency has been reviewing an article in The Washington Post published Wednesday on the Pelton case that said Pelton had compromised a costly, long-running and highly sophisticated electronic eavesdropping operation involving U.S. submarines and a high-technology device that officials think is now in Soviet hands. The Post withheld some details after appeals from Casey and other officials.

Recently, two mid-level officials -- one at the Pentagon and the other at the State Department -- were fired for allegedly leaking classified information. Sources said the firings were the direct result of a meeting on the subject of leaks among top legal advisers to these and other departments. The sources said the legal advisers had told their respective Cabinet members that the best way to deal with such unauthorized disclosures was to discipline government workers responsible.

In one case, Defense Department official Michael E. Pillsbury was fired after he reportedly failed to pass a polygraph test. Pentagon sources said he had been suspected of providing information to reporters about U.S. weapons intended for rebels in Angola and Afghanistan. State Department speech writer Spencer C. Warren was fired after he reportedly acknowledged leaking a diplomatic cable charging House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) with attempting to undermine Reagan's policy of pressure on Nicaragua.