The United States today is expected to announce cancellation of naval exercises by the Australia-New Zealand-United States alliance (ANZUS) because New Zealand has twice refused to allow port access to U.S. warships that might be carrying nuclear arms, according to a State Department official.

The joint maneuvers, called Sea Eagle 1-85, were to begin in two weeks as part of regular exercises by the three nations that form the 34-year-old mutual defense treaty.

The State Department official, speaking last night on condition that his name not be used, confirmed earlier predictions from Australian Prime Minister Robert Hawke, speaking in Belgium, that the Reagan administration plans to scrub the maneuvers.

In Wellington, Prime Minister David Lange emerged from a Cabinet meeting yesterday to say his Labor Party government would reject a second U.S. request to permit a U.S. port call in New Zealand next month because "the vessel requested was unable to meet the criteria of New Zealand policy."

A first request, made in December as part of the projected joint naval exercises in March, was rejected last week. The State Department warned then that the United States might pull out of the exercises as a result.

Yesterday, department spokesman Bernard Kalb said the new refusal by New Zealand is "a matter of grave concern, which goes to the core of our mutual obligations as allies."

He said the United States was "considering the implications for our overall cooperation with New Zealand under ANZUS, including the question of our participation in military exercises. Some decisions are expected soon; others may take longer to examine."

The situation will be on the agenda when Hawke, who supports the U.S. position, arrives in Washington today, Kalb said.

Answering questions during his stop in Belgium, Hawke said "there is probably an announcement being made now" canceling the exercises. The State Department said at the time that no such announcement was forthcoming.

In Canberra, Australian Foreign Minister Bill Hayden reaffirmed his government's willingness to take part in U.S. tests of its MX missile, scheduled later this year.

Appearing before the Senate Armed Services Committee, Defense Secretary Caspar W. Weinberger reiterated that stand, saying that New Zealand's position "constitutes a serious attack upon the effectiveness of an alliance which is absolutely essential to the security of New Zealand."

He added that Lange's government was on "a course which can only be of great harm to themselves, and I hope they'll change it."

Lange's government, elected last July on a strongly antinuclear platform, has banned all nuclear-powered or nuclear-armed vessels from its harbors. It has said it welcomes any non-nuclear ship, but the United States routinely refuses to answer questions on the nuclear status of any of its vessels. An estimated 80 percent of the U.S. fleet is capable of carrying nuclear weapons.

Other nations that oppose nuclear weaponry allow U.S. ships to dock without asking whether there are such arms aboard. New Zealand is the first to press the point.

"I would welcome [the visit] if the Americans would suggest a vessel that I know is not nuclear armed," Lange said.

He added that New Zealand plans to remain in ANZUS and that he sees no threat to the 34-year-old alliance. It is "an association which is of long standing, its end is not currently threatened, and it is impossible even in the communications emerging from the United States to detect a threat to end ANZUS," he said.

Breaking precedent, Kalb said yesterday that the vessel in question was "a conventionally powered destroyer," the USS Buchanan. However, he would not discuss either armament of the 23-year-old guided missile destroyer or the question of whether the government will in the future confirm what kind of power its ships are using.

Kalb was asked what value ANZUS has if a third of it will not cooperate on military matters. "That's a very interesting question," he replied. "That is why I made it quite clear to you that we are considering the implications for our overall cooperation with New Zealand and ANZUS."