The House yesterday voted to halt U.S. arms shipments to Chile until the government there surrenders three men indicted in the murder of former Chilean ambassador Orlando Letelier. Then, after protests from the Justice Department, the House reversed itself.

The confusing sequence of events stemmed from Tuesday's action by a federal grand jury, which indicted eight persons in connection with the 1975 car-bombing deaths of Letelier and an American friend, Ronni K. Moffitt, as they drove through Washington's Embassy Row.

Among those indicted were Gen. Juan Manule Contreras Sepulveda, former head of the Chilean secret police (DINA), and two DINA employes, Pedro Espinoza Bravo and Armando Fernandez Larios. Contreras, a close associate of Chilean President Augusto Pinochet, is believed to be the first high-ranking foreign intelligence official indicted in this country.

Yesterday, as the House was considering the fiscal 1979 foreign military aid bill, Rep. Thomas R. Harkin (D-Iowa), an outspoken human-rights advocate, introduced an amendment calling for the cutoff of all arms shipments to Chile until the three are extradited to the United States.

Congress halted military assistance to Chile in 1976 to protest alleged repression and rights abuses by the Pinochet government. However, an estimated $24 million in so-called pipeline shipments - equipment purchased or contracted for before the cutoff has been continuing.

The Harkin amendment called for halting all material in the pipeline until the three have been eradicted by Chilean authorities. After an emotional debate in which House member after member took the floor to denounce Chilean "death squads," the amendment was adopted by voice vote.

But, when word of the House's action got out, it sparked an immediate protest from the Justice Department on the grounds that it was premature and in appropriate. The department then instructed its congressional liaison officers to begin contacting members of the House to make known its objections.

Robert Keuch, deputy assistant attorney general in the criminal division, said in a telephone interview last night.

"We feel such an action is improper at the present time because the formal request to Chile for extradition hasn't been made yet, and there is no sign at this point that the Chilean judicial process will not be forthcoming in meeting the request for extradition."

Keuch said the extradition papers probably will be filed within the next two weeks, and added that it's likely to take some time before the matter is decide by the Chilean courts. He said Justice was aware of news agency reports from Santiago quoting Pinochet as saying there was some doubt about whether the three Chilean nationals will be extradited.

But, Keuch added, the interests of justice require that the appropriate legal channels be used and given an opportunity to work without actions that could be construed as undue political interference.

Privately, other Justice Department sources said actions like the House amendment could seriously impede efforts to bring the three Chileans to trial, because it could be cited within Chile as an interference by Congress in its internal affairs and a politically inspired maneuver to topple the Pinochet government.

The arguments made by the Justice Department apparently had considerable impact within the House. Late in the afternoon, Rep. Charles E. Wiggins (R-Calif.) moved to reconsider the Harkin amendment, and, on that go-around, it was overturned on a roll-call vote, 243 to 166.

In the indictment, Contreras and Espinoza, DINA operations supervisor, were charged with plotting the assassination of Letelier, an outspoken foe of the Pinochet government. Fernandez Larios was named as being one of two DINA agents - the other being an American citizen. Michael V. Tonley - who came to the United States to carry out the plot in cooperation with militant Cuban exiles.