Muldoon pulls the starting gun early. New Zealand leader takes risk by calling for election ahead of schedule

New Zealanders go to the polls July 14 in an election called by Prime Minister Robert Muldoon, whose three-year term in office was not due to expire until November.

The early poll is a calculated gamble by Sir Robert, prime minister since 1975, whose National Party won the last three general elections but was clinging to an overall majority of only one in the 92-seat House of Representatives.

Opinion polls indicate the vote will be a cliffhanger in a two-party race between the Nationals - who have ruled this Pacific nation of 3.2 million people for 21 of the last 24 years - and the Labor Party.

The latest poll shows National leading Labor 44 percent to 43 percent in popular support, trailed by the minority New Zealand Party, which is contesting its first election, and the Social Credit Political League.

It is the first time in 33 years that a New Zealand leader has called an election without serving out his full three-year term.

The prime minister said he had been forced to seek an early poll by the actions of two dissident members of his party, Marilyn Waring and Michael Minogue, who voted with the opposition last week.

The government was saved from defeat by the votes of two independent members of Parliament, both former members of the Labor Party. Ms. Waring, who had earlier announced she would retire from Parliament at the scheduled November election, later said she would boycott party meetings.

Unable to rely on her vote in future, Sir Robert said: ''You can't govern on that basis. I'm just asking the people: Give me a majority for what we've been trying to do.''

There are issues, but it promises to be a bitter, if brief, campaign fought on the personalities of the two main party leaders.

Sir Robert is pinning his hopes on his personal standing in the country. The last opinion poll showed 34 percent of voters named him their choice as prime minister, against only 13 percent for Labor's David Lange, who is fighting his first election as party leader.

When issues are discussed, the state of the economy is certain to head the list.

Sir Robert, who is also minister of finance, claims New Zealand, which has been hard hit by the world recession, is pulling through after its most difficult time since the 1930s.

Mr. Lange says the government's economic performance has been appalling, leaving the biggest deficit in the country's history.

Some commentators, pointing out that the government had managed with a single-vote majority since 1981, suggest the real reason for the early poll is that the economic situation will worsen by year's end.

They say the rate of inflation, slashed from 17 percent in 1982 to 3.5 percent recently by a wage-and-price freeze, is mounting again, now that prices can rise.

The deficit and the cost of servicing massive borrowing will pose serious problems later in the year, they say, which could only be headed off by raising taxes and cutting government spending. The early election means the government will not have to produce a budget before the vote.

Analysts note that unemployment, which hit record levels this year, has dropped in each of the last four months, but is tipped to rise again.

The prime minister may also see immediate vote-catching potential in recent measures to cut interest rates and clamp down on militant labor unions.

Special regulations have limited mortgage interest rates to 11 percent for a first mortgage and 14 percent for a second, and a top mark of 17 percent has been set for lending on such things as automobiles and appliances.

Last week, Parliament passed a bill outlawing strikes at the nation's only oil refinery, which had been plagued by many stoppages over the past few months.

The prime minister says the strikes, which threatened gasoline supplies, have ''sickened'' ordinary New Zealanders and he's hoping that dissatisfaction with the unions (traditionally Labor Party supporters) will rub off onto his opponents.

Foreign affairs seldom play a big part in New Zealand elections, but relations with the United States could figure this year.

The Labor Party wants to ''renegotiate'' the ANZUS defense treaty with the US and Australia to accommodate its policy of a nuclear-free zone in the South Pacific. Labor says it would ban port visits by American nuclear-powered and nuclear-armed vessels.

Sir Robert says such visits are a cornerstone of New Zealand's defense policy. A ban would wreck relations with the US, he says.

(US Secretary of State George Shultz was due in Wellington July 16 for the annual ANZUS Council meeting. It is expected this will now likely be postponed because of the election.)

About 2 million New Zealanders are expected to vote for MPs in the expanded 95-seat parliament.

Voters will also cast ballots in a traditional liquor poll, in which they can vote for prohibition. In 1981, 22 per cent of them did so.