Australia has agreed to provide New Zealand with more data from its intelligence operations in the South Pacific and Southeast Asia in a major step to shore up relations following the cutoff of American defense cooperation and intelligence to New Zealand.

As part of the agreement, the armed forces of the two countries will also increase their joint military exercises to compensate New Zealand for the U.S. withdrawal from the annual ANZUS exercises, Australian Defense Minister Kim Beazley said yesterday. He was returning from a five-day visit to Wellington, the New Zealand capital.

Since New Zealand banned visits to its ports by U.S. nuclear warships in February, the United States has cut off bilateral or multilateral military exercises with New Zealand, restricted the flow of intelligence and limited contacts with New Zealand personnel in consultation and training.

The dispute has strained relations between the United States and New Zealand, which are linked with Australia in the mutual defense alliance known as ANZUS. Beazley's visit marked a move by Australia to keep the friendly ties with its neighbor across the Tasman Sea without exacerbating U.S. sensitivities over New Zealand's ban on port visits.

When Washington cut off the flow of intelligence to New Zealand, Australian Prime Minister Robert Hawke declared publicly that Australia would not pass on U.S. intelligence to New Zealand.

Beazley repeated that promise this week and said at a press conference in Wellington before returning home that the U.S. prohibition on American-sourced intelligence being passed on to New Zealand would be "observed to the letter."

But, he said, "We do intend to provide New Zealand with intelligence of Australian origin."

To avoid the possibility that some U.S.-based intelligence could be passed on to New Zealand, Australia will set up a separate intelligence analysis bureau in its Defense Department in Canberra to pass on Australian assessments of Australian-originated intelligence, he said.

The Reagan administration's cutoff of all but the most vital intelligence to New Zealand was the most militarily harmful of all the administration's decisions. New Zealand has only a limited capability for obtaining intelligence information on its own. But since the late 1940s, it has been a member of the network of U.S., British, Canadian, Australian and, until February, New Zealand agencies that have shared intelligence secrets.

Since 1952, when the ANZUS treaty went into effect, the intelligence flow among the United States, Australia and New Zealand has been especially large. Because Australia has been able to establish intelligence operations in Southeast Asia more easily than the United States, its contributions have been considerable.

Beazley said that existing liaison arrangements between New Zealand and Australia will be retained as far as possible and that New Zealand intelligence officers will have access to Australian intelligence agencies.

Australia's intelligence network, which works closely with the U.S. Central Intelligence Agency, National Security Agency and intelligence divisions of the Pentagon and State Department, will keep any information originating in the United States or gathered in coordination with the U.S. agencies for Australian eyes only.

Beazley said the "intensifying" of traditional defense cooperation between New Zealand and Australia will not threaten the United States.

New Zealand also agreed to become more self-reliant in its own defense and increase its defense expenditures, Beazley said.

The two sides also agreed that New Zealand would contribute its small but highly regarded underwater warfare research to increasingly active Australian research on port and sea lane mining, he said.

New Zealand, a nation of 3 million people, currently spends about $272 million on defense. Australia, with five times New Zealand's population, spends more than 10 times that amount on defense.