SYDNEY, JUNE 20 -- Three years ago, when Australia held its last national elections, U.S. security interests in this part of the world seemed under siege by a highly visible antinuclear movement.

Today, Australia once again is in the midst of a national election, but the worst fears of U.S. officials have yet to be realized.

Under the leadership of Prime Minister Bob Hawke -- a blunt-talking former union leader with a mastery for maintaining the political middle ground -- Australia's Labor Party government has proved itself more interested in staying in power than in promoting a more idealistic foreign policy platform.

"There's no doubt there's been a swing to the right," said veteran activist Peter Jones, a research officer for the tiny Nuclear Disarmament Party's only elected politician. After its peak during the 1984 campaign, he said, the antinuclear lobby "hasn't had any impact on the Australian public."

This year, the antinuclear issue has raised barely a whisper. The Nuclear Disarmament Party -- which drew a half-million primary votes three years ago in an electorate of 9 million -- no longer exists.

Peter Garrett -- the shaven-headed lead singer of the rock group Midnight Oil, who drew extraordinary media attention to the antinuclear issue in the past -- has decided this election to spend more time on his music and with his family.

The antinuclear policies of the Labor Party government in neighboring New Zealand have caused a deterioration of relations with the United States and the breakup last August of the 35-year-old ANZUS defense alliance.

After Prime Minister David Lange pressed ahead with his party's promise to prohibit port calls by nuclear-armed and nuclear-powered warships, the United States withdrew its guarantee of military protection and ended most intelligence sharing and military equipment sales.

When Secretary of State George P. Shultz and Defense Secretary Caspar W. Weinberger begin an annual series of meetings here this week with their Australian counterparts on defense and foreign policy issues, it will likely be a cordial meeting of like-minded "mates."

Relations between the conservative Republican administration in Washington and the Labor government in the Australian capital of Canberra have remained on firm and friendly ground.

Meanwhile, Australia's antinuclear lobby -- which prefers the label "peace movement" -- is left with nowhere to go. Shortly after its modest 1984 success, the Nuclear Disarmament Party was taken over by a radical left-wing Trotskyite faction and eventually collpased.

Jo Valentine, the only NDP senator, is running for reelection this year as an independent from her district in western Australia.

The antinuclear left within the ruling Labor Party likewise has decided the best strategy is to stay quiet.

"We have neutralized that debate," said Labor Party organizer Ian Henderson. "While there'll be a number of people in the party who will not be happy with the government's position, they are not out to destabilize the government on that issue."

The contrast between the Labor governments in Wellington, the New Zealand capital, and Canberra speaks volumes about the differing attitudes of New Zealanders and Australians about their place in the Pacific region and their role in the superpower equation.

Ask New Zealanders which foreign country they most closely identify with and the overwhelming majority say Australia, according to a public opinion poll.

Ask Australians the same question and almost two-thirds mention the United States.

"That, I think, explains the discrepancy," Jones said. "New Zealand is so small and so far away that the Soviet Union isn't going to risk a world war by invading it. It's a small country with a high environmental concern.

"Australia, on the other hand, is a big country, it's closer to Asia, it has heavy trade and a lot of natural resources."

Antinuclear activists say they now recognize that Australians overwhelmingly support the security relationship with the United States.

According to the most recent poll by the Morgan Research Center, 75 percent of Australians favor maintaining the defense alliance with the United States.

Despite showing support for the alliance, however, Australians remain largely antinuclear in the surveys -- suggesting that while the issue is dead for now, it could be revived.

Besides allowing port calls by U.S. warships, Australia is also home to key U.S. communications facilities, at Pine Gap near Alice Springs in central Australia, at Nurrungar to the south, and a vital long-range submarine and ship communications base at the tip of North West Cape in the west, which sends out messages to an area covering Southeast Asia and the Indian Ocean.

The facilities at Pine Gap and Nurrungar receive a variety of information from orbiting U.S. satellites, to help detect Soviet missile launchings. In the 1984 election, those bases emerged at the center of the antinuclear controversy, with accusations by the disarmament advocates that the data being received there would also help the United States plan a nuclear first strike.

The antinuclear question that year emerged as perhaps the single captivating issue of an otherwise dull and unusually long (for Australia) seven-week campaign. But after that, the movement simply disintegrated.

Most Australians interviewed also agree that the average "Aussie" tends to be a bit apolitical, more interested in weekend sports than in debate over nuclear disarmament.

The decline of the movement here, however, is due largely to the deft political maneuvering of Hawke, who has managed to defuse the issue partly by co-opting it. Through some careful backpedaling on his own party positions, Hawke has managed to keep his American allies happy and his antinuclear credentials intact.

He has held steadfastly to his position against Australia ever acquiring its own nuclear weapons. He is the most outspoken critic in the region of French nuclear testing in the Pacific. And he has led the charge for declaring the South Pacific a nuclear-free zone. He signed the South Pacific Nuclear-free Zone treaty, which the United States adamantly opposes.

When the Reagan administration offended Australia twice last year with separate decisions to subsidize U.S. wheat sales to the Soviet Union and to sell a surplus sugar stockpile to China, Hawke vigorously protested. But he resisted calls from some farmers' groups, who wanted to link American trade practices to the continued presence of U.S. military bases.

Without fanfare, Hawke also managed to reverse Labor's position against uranium sales to France, much to the ire of leftists and peace activists.

As a result of pulling his party to the right, both on foreign policy and economic issues, Hawke has angered and alienated Labor's once dominant, now insignificant left wing.

But political analysts here say Hawke largely has co-opted the conservative opposition, positioning himself to become the first Labor prime minister to win a third consecutive term in the elections on July 11.