WASHINGTON (AP) _ The Bush administration said Friday it will urge the United Nations to permanently ban international drift-net fishing, closing loopholes in a previous U.N. resolution allowing some use of the nets.

Sen. Ted Stevens, R-Alaska, said the push for a permanent ban with no exceptions ''is the knockout punch we have been looking for.''

''Without this new initiative, there is the possibility that outlaw drift- net fleets will be able to sail through a loophole in the moratorium,'' he said.

Assistant Secretary of State Janet Mullins said U.S. officials will undertake ''a major diplomatic effort'' in the United Nations this fall to secure a permanent ban on all large-scale, high-seas drift nets effective June 30, 1992.

The U.N. already has approved a resolution banning the environmentally destructive nets next summer, but that measure allows countries to continue using them if they can prove conservation efforts are underway to protect marine species.

Drift nets are used primarily by Japan, Taiwan and South Korea to catch squid in the Pacific Ocean. They stretch as long as 30 miles and critics say they indiscriminately kill all marine life in their path.

The new assault on the so-called ''curtains of death'' was outlined in a letter from Mullins to Stevens. She told the senator that Secretary of State James Baker agrees that the existing U.N. resolution is inadequate.

Stevens said, ''No amount of conservation efforts can make up for the destruction caused by these curtains of death.''

The announcement comes after the Commerce Department this week imposed a new regulation banning U.S. imports of any fish or fish products caught with drift nets after June 30, 1992.

Japan, Taiwan, South Korea and France will be required to certify that fish products sold to the United States were not caught with drift nets.

The Bush administration notified Taiwan and South Korea last month that they will face trade sanctions if they continue to fish with the nets. The Taiwanese government since has announced it will comply.

Alan Macnow of the Japan Fisheries Association based in New York City said research has shown that drift nets do not kill all marine life in their path. He said drift-net fishing is only carried out across about 0.5 percent of the North Pacific.