In a news conference complete with long-distance telephone hookups, a former hostage and hostage family members, Rep. George V. Hansen (R-Idaho) yesterday repeated his call for a congressional inquiry into America's involvement in Iran.

Similar calls for hearings have been made by Iranian officials, who also have demanded that the United States admit wrongdoing in Iran in return for the release of 50 Americans who have been held hostage in the U.S. Embassy in Tehran since Nov. 4.

However, Hansen said his proposed probe's purpose is not to appease Iranian officials.

The inquiry would be held to ascertain the truth about America's official relationship with Iran, said Hansen, who went to Tehran last November on a personal mission to help the hostages.

He said U.S. taxpayers and consumers want congressional hearings "to find out just what happened in Iran."

Bonnie Graves, wife of embassy hostage John E. Graves, agreed.

"We must get congressional hearings going on this matter . . . Anything that Congress can do will be of great benefit to all of us in this," said Mrs. Graves, who attended the news conference.

Former Marine Corps. Sgt. William E. Quarles, one of a group of 13 blacks and women released by the Iranian militants soon after the seizure of the U.S. Embassy, said a congressional inquiry into U.S.-Iran relations might hasten the release of his still-captive colleagues.

"I think it would be very important in getting them out," said Quarles, who has finished his enlisted tour of duty with the Marines and is now preparing for studies at the University of Uppsala in Sweden.

The parents of Army Warrant Officer Joseph M. Hall, who is among the American hostages in Tehran, told reporters in an amplified telephone conversation that they personally appealed to President Carter several months ago to hold congressional hearings on U.S. relations with Iran.

"I look forward to this," said Zane Hall, the hostage's father."We should have a hearing . . . . If we are not guilty [of wrongfully interfering in Iranian affairs], then we have nothing to hide."