House Speaker Jim Wright said Wednesday "no member of the House is under investigation" in the Pentagon bribery and fraud investigation, and he criticized leaks linking members of Congress to the probe as "a despicable thing."

The Texas Democrat's statement came as Henry Hudson, the prosecutor in charge of the investigation, planned to meet with members of Congress who want to know how far - and how high - the investigation is likely to reach.Wright said he had been told by House lawyers that no subpoenas have been issued for House members nor has any information been sought by investigators.

Five House members have been reported as being under scrutiny, although they have said they are not involved. They are Reps. Bill Chappell, D-Fla., chairman of the House defense appropriations subcommittee; Thomas Downey, D-N.Y.; Samuel S. Stratton, D-N.Y., chairman of the House Armed Services procurement subcommittee; and Andrew Ireland, R-Fla., and Rep. Roy Dyson, D-Md., both members of Stratton's subcommittee.

Wright criticized what he said are unfair leaks.

"I think it's thoroughly outrageous that people would be leaking statements that (are) thoroughly untrue, absolutely unfounded," he told reporters. "I don't think it is in anyway honorable for members of the executive branch . . . to maliciously leak the names of innocent members of Congress with the expectation they can start rumors."

At the Pentagon, the Defense Department said in a statement that former Navy Secretary John Lehman Jr., had not been briefed on the probe, which was started by the Naval Investigative Service in September 1986.

"When he was still in office, the scope of the investigation did not indicate that it was necessary to brief him," the Pentagon said in a statement. "Only later did it become clear that the matter warranted the attention of the secretary of the Navy."

One wiretap picked up a conversation which can be interpreted as suggesting that Lehman warned his former procurement aide, Melvyn Paisley, about the investigation, sources said.

Lehman resigned his post and returned to private industry in April 1987.

One figure implicated through wiretaps in the case, meanwhile, has agreed to cooperate with Hudson's prosecutors and another is on the verge of agreeing to tell what he knows, according to sources familiar with the case.

It could not be determined whether the target who is cooperating is a Pentagon employee, a consultant or a defense contractor.

The case involves allegations that defense contractors and consultants, many of whom are former Pentagon employees, paid bribes to Pentagon officials for inside information about planned weapons. The details could be vital in winning contracts worth billions of dollars.

President Reagan, at a news conference at the end of the economic summit in Toronto, said that he was "very upset" about the reputed scope of the problem, but said "I should think it should be understandable how such things can happen in something as big as our government is."