The House ethics committee is unlikely to conclude its investigation of Speaker Jim Wright until early next year, members of the panel say.

While most witnesses relevant to the case have been interviewed, the special counsel handling the case, Richard J. Phelan, still has not written a final report, the lawmakers said after a 30-minute status session Wednesday."It will be next year" before the case is wrapped up, said Rep. Thomas Petri, R-Wis. "We've still got some loose ends to tie up."

Asked whether the investigation will extend into 1989, Rep. John T. Myers, R-Ind., replied: "I think you can make book on that."

Myers said the six GOP members of the 12-member committee all were reappointed Wednesday to new terms to provide continuity at least until the Wright inquiry is completed.

No committee members would comment on results of the investigation thus far. The panel could dismiss the charges or it could issue a statement of alleged violations, the congressional equivalent of an indictment. That would trigger a disciplinary hearing and possible sanctions.

Wright, D-Texas, has been under investigation since June on allegations he improperly used his office for financial gain and wrongly used his position to lobby federal officials on behalf of Texas interests.

Ethics committee Chairman Julian Dixon, D-Calif., said Phelan still has to review mounds of information collected in the investigation and write a final report. The panel then can vote to release the report or use parts of it in writing its own conclusions, Dixon said.

Phelan would not speculate as to when the report would be completed, but added: "I don't think it's going to take months."

He said the House panel, formally called the Committee on Standards of Official Conduct, had been "very supportive . . . We said we wanted to do a full and fair and complete investigation, and we have been permitted to do it."

Phelan had no comment on complaints that Wright's lawyer, William Oldaker, also represents a half-dozen other figures in the ethics case.