The House of Representatives reprimanded Rep. Austin J. Murphy (D-Pa.) yesterday for violating House rules by letting someone else cast votes for him on the House floor, keeping a "ghost employe" on the payroll and diverting congressional resources to his former law partner.

Murphy indignantly denied most of the charges and claimed he is guilty of nothing more than being "compassionate" to an absentee staff member, but the House sided overwhelmingly with its ethics committee, which said the evidence against the six-term Democrat is "clear and convincing."

The vote was 324 to 68.

The sanction was the mildest form of disciplinary action the House could have taken. Murphy fought hard in the floor debate, but then put it in perspective in a news conference before the vote was complete.

Many of the members who voted against him, he said, "were telling me, 'Well, this is only a reprimand, and it's a slap on the wrist . . . . It's really not something you have to worry about.' There is, of course, nothing that interferes with seniority or committee assignments or committee chairmanship."

The disciplinary action, the first of any kind against a House member since 1984, came amid growing complaints that the ethics panel has abdicated its responsibilities in the face of repeated instances of congressional misconduct. Critics contend that allegations against high-ranking House Democrats, including Speaker Jim Wright (D-Tex.), are being swept under the rug.

The crossfire added partisan spice to the debate. Rep. Newt Gingrich (R-Ga.) cautioned against making Murphy "a scapegoat" and urged that Wright be investigated and that inquiries into House Banking Committee Chairman Fernand J. St Germain (D-R.I.) and Rep. Mary Rose Oakar (Ohio), vice chairman of the House Democratic Caucus, be reopened.

Rep. Tommy F. Robinson (D-Ark.) jumped up to protest that Gingrich was out of order.

"That makes my point," Gingrich replied. "You do not have the courage at this moment to raise these charges against those in power. It is sort of shameful."

For his part, Murphy picked up on the theme, contending that he had been "singled out" and subjected to "Star Chamber" proceedings on the basis of flimsy evidence.

Murphy said he was still baffled as to how he had been recorded as having voted on two occasions in July and August of 1978 when he was admittedly in Pennsylvania.

He said he had no idea that his home district staff had let his former law partner, Jack France of Charleroi, Pa., use congressional photocopying equipment, furniture and long distance service after Murphy was elected in 1976.

And Murphy said he didn't find out until a few weeks before dismissing him that a subcommittee staff director he had hired had been regularly absent from the office to care for his ailing mother.

"If I was stupid and compassionate, then that's my fault, but that's the only thing I permitted," Murphy said.

Rep. Julian C. Dixon (D-Calif.), chairman of the ethics committee, retorted in a stinging summation that Murphy was "trying to cloud" the issues. He said the evidence clearly showed someone had used Murphy's voting card on the House's electronic tally machine twice in 1978 and that it was plainly against House rules.

As for the use of congressional supplies by Murphy's former law partner, Dixon said, "The evidence is that this took place over nine years." Finally, Dixon charged, Murphy roomed with the ghost employe, Michael Corbett, who supposedly was absent without Murphy's knowledge.

"If you think that . . . gets him off the hook, so be it," Dixon told the House of Murphy's excuses. "If you think we're in any way picking on this man, vote no."

Other members of the ethics committee, formally known as the Committee on Standards of Official Conduct, said they had spent more time on Murphy's case than any other in the 1980s and that the evidence against him is "overwhelming." Rep. Vic Fazio (D-Calif.) said the four counts against Murphy reflect "a pattern of abuse" that is persuasive. "We are not scapegoating any member," Fazio said.

The investigation by the ethics panel began following publication of a report on Murphy's activities last May in The Washington Times.