New Zealand Ambassador Wallace Rowling says his government has offered to increase its nonnuclear military activities in the Pacific to compensate for withdrawing from nuclear weapons arrangements with the United States.

Rowling said in an interview that such a plan could be part of "a new base line" for continuing cooperative relations between the two countries, which have slumped since New Zealand refused to permit a port call by a U.S. warship on the grounds that it might be carrying nuclear weapons.

"We gave an indication this [conventional military activity] would be the way we would like to go," Rowling said, but he said U.S. officials do not seem interested.

Rowling, a former leader of the New Zealand Labor Party that turned policy against nuclear ship port calls after its election victory last July, said the chances are "nil" that the party will reverse its nonnuclear stand. He also said there is "no way the government is going to come down on this issue." The next New Zealand election would not be expected until late 1987 under usual political timetables.

The Reagan administration has maintained that New Zealand's refusal to accept nuclear-armed U.S. ships is a breach of the military alliance relationship set forth by the 1951 ANZUS (Australia, New Zealand, United States) Treaty. Early last week, the State Department informed New Zealand Prime Minister David Lange that it is drastically curtailing military cooperation and intelligence sharing between the two countries.

Secretary of State George P. Shultz has told Congress that the ANZUS alliance is not being formally abrogated, but indicated that it will be maintained in an inactive status while the dispute continues. Some U.S. officials have cast doubt on whether the traditional midsummer meeting of the ANZUS council, which involves the foreign ministers and other high officials of the three treaty allies, will be held this year.

Rowling took sharp issue with a report that New Zealand had threatened to "retaliate" against the United States by reducing its military activities in the Pacific. He said any thought of retaliation would be "ludicrous" and likened it to "a flea biting an elephant's backside."

Lange was simply describing realities, the ambassador said, when he said in a speech in Los Angeles Tuesday that diminished U.S. security cooperation with New Zealand would "diminish our capacity to go on playing a role" in the security of Southeast Asia and the South Pacific. "We intend to continue to fulfill our responsibilities" for security in the region, Rowling said.

In the period ahead, Rowling said, "We'll be constantly reminding the United States that there is a series of counterproductive effects" to the quarrel with New Zealand over nuclear matters. "If you want to stir up a nationalistic fervor in a country, you couldn't do a better job," Rowling said.