A House committee voted along party lines yesterday to step up an investigation into allegations of illegal partisan political activity in the Interior Department, but held off on a threat to hold top officials of the agency in contempt of Congress.

Republicans on the House Resources Committee charge that Interior officials illegally passed negative allegations about GOP lawmakers to the Democratic Congressional Campaign Committee. By a 24 to 14 vote, the committee yesterday gave its chairman, Rep. Don Young (R-Alaska), blanket authority to issue further subpoenas in the matter without consulting the full committee as is normally required.

At issue is a dispute between House Republican leaders and the Clinton administration over policy toward the Commonwealth of the Northern Mariana Islands, a U.S. territory in the western Pacific facing allegations of labor and human rights violations.

Democrats have charged that key House GOP leaders have improperly used their positions to block reform on the islands.

Young said he had received "serious allegations of illegal actions by employees of the Office of Insular Affairs," the Interior Department bureau that deals with U.S. territories. He said the allegations involve violations of the Hatch Act -- which bars government employees from using their offices for partisan purposes -- and the "misuse of federal resources" in ways that "effectively undermine the democratic process." He said a "partial response" to subpoenas that were served last week "seems to bear out our concerns."

The ranking Democrat on the committee, Rep. George Miller of California, said he does not condone partisan activities by federal employees and that, if true, the alleged conduct was "outrageous."

But he suggested that the investigation served to divert attention from the exploitation and abuse in the Marianas of thousands of foreign workers, most of them impoverished women from Asia. While Young was quick to investigate the department, he has refused for nearly three years to hold any hearings on the underlying problems on the islands, Miller said.

Young said that although Interior had already missed a deadline to respond to subpoenas, he would withhold a contempt resolution "for now" and give the department more time to comply.

Those subpoenas demanded awide array of materials from top officials at Interior and the DCCC. Among other things, they sought computer files from David North, the spokesman for the insular affairs office, "related to or mentioning any Member of Congress," notably House Majority Whip Tom DeLay (R-Tex.) and House Majority Leader Richard K. Armey (R-Tex.) and Sen. Frank H. Murkowski (R-Alaska).

The Interior Department's solicitor, John D. Leshy, said in a letter to Young that, as worded, the subpoenas require a "massive" document search and the cost would be "staggering."