New Zealand's Lange tries to mollify US

New Zealand's new Labour Party prime minister, David Lange, has gone out of his way to head off a potential crisis over this country's defense relationship with the United States.

In a surprise move, Mr. Lange, who was swept into power in Saturday's general election after campaigning on an antinuclear policy that would ban US nuclear warships from New Zealand ports, flew 400 miles to greet Secretary of State George Shultz.

Mr. Shultz flew into Wellington Sunday for the annual meeting of the ANZUS pact, a 1951 defense alliance linking the US and New Zealand with Australia. The meeting opens today.

Labour's campaign policy called for a ''review'' of ANZUS, which it claims is outdated. American officials reject this and say New Zealand port visits by US ships are vital to the pact's future.

The defeated National Party government of Sir Robert Muldoon - which fully supports ANZUS - will represent New Zealand at the two-day meeting because the Lange administration will not be sworn in for two weeks.

Lange is scheduled to meet Shultz for separate talks Tuesday. His decision to fly from his home in Auckland to greet Shultz was seen as a conciliatory move to defuse talk of a clash between the two nations.

It was a formal airport greeting with no discussions, but the two shook hands warmly and Shultz congratulated Lange on his election victory. Neither spoke to journalists.

During the campaign, Lange, a Labour moderate, denied that the antinuclear policies and ANZUS revision proposed by his left wing were anti-American. ''I am completely resolute that the United States is a most valuable ally and trading partner and it is inconceivable that we should fall into a bad relationship with that country,'' he said.

Labour won 56 of the 95 seats in the expanded House of Representatives, the National Party, 37. The minority Social Credit Party won two seats although its leader, Bruce Beetham, was defeated.

It was only the third time in 35 years that Labour had won a general election. The National Party has ruled since 1949 except for one-term Labour governments in 1957 and 1972.

The result was a personal defeat for Sir Robert Muldoon, National's prime minister since 1975. He had called the snap election to try to boost his working majority of one in the last Parliament.

Labour's first task is the economy. An International Monetary Fund report on New Zealand, leaked to the press during the campaign, cited serious imbalances and high levels of internal deficit and foreign debt. The IMF said the government faced ''unattractive policy options,'' including devaluation of the New Zealand dollar, cuts in public spending, and higher indirect taxes.

One of Lange's first actions will be to convene an economic summit meeting of unions, employers, and government to thrash out a ''social accord'' with new price control and wage-fixing mechanisms.

Lange has pledged a new style of ''open government'' and promised a bill of rights (New Zealand has no written constitution) and an affirmative action program to get more women into top public service positions.