Increasingly volatile S. Pacific troubled by nationalism and unfulfilled hopes. Economic dependency, rising birthrate stoke tensions in island nations

The South Pacific is no longer so pacific. The region that has symbolized the idyllic life for many Westerners has become increasingly volatile over the past year.

Rising indigenous nationalism, growing populations with unfulfilled expectations, and a new generation of more radical, post-independence leaders are spawning problems in several fledgling island nations.

Development has come slowly and with difficulty for these countries because of their remoteness from outside markets, heavy dependence on overseas economic aid, high birthrates, low education levels, and regular havoc-wreaking cyclones.

Vanuatu. This island nation has just celebrated eight years of independence from its joint colonizers, France and Britain. But the prospect of violence hangs over it as the government confronts its worst constitutional crisis since decolonization.

Last week, the power struggle between Walter Lini - the first and only prime minister of Vanuatu - and former Cabinet Minister Barak Sope resurfaced.

Mr. Sope is challenging Fr. Lini for the premiership. Lini has responded by booting Sope and four supporters out of Parliament. Sope countered with a boycott last week which included half of Parliament's members. Thursday, Lini had the entire opposition party expelled from Parliament for supporting the boycott. Sope has called the acts unconstitutional and called for Lini to step down.

The future of Lini's government may hang on a Supreme Court ruling, scheduled for this week, on the legality of the half-full parliamentary sittings.

Fiji. For the 17 years following independence from Britain, Prime Minister Ratu Kamisese Mara ruled. Then in April 1987, he lost the election. Two bloodless coups followed, and ties with the Commonwealth were severed. Ultimately, the premiership was bequeathed back to Ratu Sir Mara. But the younger man behind the coups, Brig. Sitiveni Rabuka, is considered in charge.

The discovery in June of smuggled arms - including several tons of machine guns, rocket launchers, and grenades - led Brigadier Rabuka to impose sweeping internal security measures. These resulted in several detentions, including the arrest and alleged beating of an Australian who was accused of taking pictures of a Fiji Army barracks.

New Caledonia. Bombing, hostage-taking, and shootings were among the tactics employed by militant native Kanak separatists and anti-independence vigilantes during French elections. Twenty-eight people died on this French island territory in April and May.

A relative calm has followed under France's new premier, Michel Rocard. He has orchestrated an agreement for governing the territory between those who favor and oppose independence. The plan calls for New Caledonia to be divided into three regions and to be locally administered by Kanaks and pro-French settlers. A referendum on independence is slated for 1989. The ruling Conservative Party ratified the accord last week. But Kanak leader Jean-Marie Tjibaou has been unable to get the endorsement of the main separatist group, the Kanak Socialist Liberation Front.

Taken together with the revolving-door premiership in Papua New Guinea, October riots in Tahiti, and simmering racial unrest in New Zealand, the pattern is one of increasing volatility.

Though the troubles may seem small by world standards, even a minor instability can drastically alter the direction of these states and their infant economies. As Savenaca Siwatibau, former governor of the Fiji Reserve Bank, said recently: ``Political independence is one thing, economic independence is another.''

It's often difficult to reconcile the expectations of a better life that have come with decolonization. Improved communication and transportation have also made islanders more aware of the life styles of the outside world.

``What's troubling the Pacific is no different from what's troubling other parts of the world,'' says Prof. John Connell of Sydney University. ``In Suva, Port Moresby [Papua New Guinea], Honiara [Solomon Islands], and Port Vila [Vanuatu] you have rapidly growing populations creating pressure on the land and urbanization without employment. People want wages - to feed families and buy decent clothes - just like we do.''

Professor Connell says younger leaders can use such frustrations to make political headway against the ``older'' leaders who may be associated with the unfulfilled expectations of independence.

The rise of indigenous nationalism in recent years has also contributed to instability. In New Caledonia, Fiji, Tahiti, New Zealand, and even Australia, native inhabitants are trying to regain control of land and power they feel has been unjustly taken by settlers of the last century. In Fiji, for example, Rabuka led the coups. But the Taukei Movement, which wants to return ``Fiji to Fijians,'' was the behind-the-scenes instigator. Rabuka overthrew Fiji's first Indian-dominated government. Indians, brought to Fiji as indentured farm workers a century ago, now slightly outnumber the population of native Fiji islanders.

What's fueling this indigenous nationalism now? History professor Alan Ward of the University of Newcastle, Australia, cites three factors: a more-educated native leadership, urbanization, and rising birth rates.

Natives of New Caledonia, New Zealand, and Australia are being heard now, he says, because ``their own lawyers, academics, and media people can present their demands more articulately. That's a major factor in recent years.'' Urbanization has brought tribes together and focused their message. Previous indigenous rights protests were often sporadic and isolated in rural pockets, he adds.