ZIZERS, Switzerland (AP) _ Zita, the last empress of the vast Hapsburg empire whose role in a plan to end World War I led to exile from her Austrian palace, died today. She was 96.

Born in Italy as a princess of Bourbon-Parma, Zita was the widow of Charles I, the last crowned head of the Hapsburg dynasty that ruled for 640 years.

She died at 1:30 a.m. at Johannes-Stift, a home for the aged in this wine- growing village on the Upper Rhine. A spokesman for the House of Hapsburg, Bernd Posselt, said Zita ''just faded away'' after ailing for some time.

A private funeral was scheduled Wednesday in Switzerland.

Zita will lie in state for three days at St. Stephen's Cathedral in Vienna. A requiem Mass is to be held April 1, the 67th anniversary of the death of Charles I. She is to be interred in the Hapsburg vaults of Vienna's Capuchin Church.

Zita had lived at Johannes-Stift the past three decades. Two plainly furnished rooms were the home of the woman who once held court at the Versailles-sized castle of Schoenbrunn in Vienna.

Her husband ruled over a multilingual empire of 50 million people stretching from what is now Poland to the Mediterranean. After the Allied victory in World War I, he agreed to ''temporarily relinquish'' his imperial rights. He never officially abdicated.

Zita, a mother of eight and a Roman Catholic, wore mourning black from the time Charles died in exile on the island of Madeira in 1922.

Tragedy surrounded the ascent of her husband.

He was crowned emperor of Austria and King of Hungary after the death in 1916 of his uncle, Francis Joseph, who reigned 68 years.

Francis Joseph's wife, Elisabeth, was fatally stabbed by an Italian anarchist in Geneva in 1897. Their son, Crown Prince Rudolf, killed himself in a suicide pact with his mistress in 1889. Their nephew, Francis Ferdinand, the heir presumptive, was shot by a Serbian assassin in 1914, triggering World War I.

Charles I initiated moves in 1916 to negotiate a peace he hoped would save the Austrian monarchy. Zita helped arrange secret contacts with the Allies.

The go-between was her brother, Prince Sixtus of Bourbon-Parma, then serving in the Belgian army, who was in touch with French President Raymond Poincare. In turn, Poincare notified King George V of Britain.

The Austrian efforts were revealed in 1918, causing an uproar and rocking the Austrian-German alliance. Zita became known as the ''spy of the Bourbons.''

The 1918 exodus from Schoenbrunn Castle was the beginning of a long odyssey.

Charles took exile in a Lake Geneva chateau at Prangins, Switzerland. But after launching from there an abortive combeack attempt, he was banished to Madeira, where he died a year later at 34.

A widow at 29, Zita turned down invitations from royal relatives and instead chose to bring up her children in modest environments, first in a Spanish fishing village and then in the Belgian countryside where she raised chicken and sheep.

Hitler's Blitzkrieg sent the family fleeing to Canada and the United States where they lived at Tuxedo Park, N.Y. After the war, Zita toured American cities to promote humanitarian aid for Europe.

In the early 1950s, she returned to Europe and settled at Zizers, a few hours drive from the postwar home of her oldest son, Otto von Hapsburg. She curtsied before him when Otto, at age 18, became the new titular head of the Hapsburg dynasty.

Although the Austrian border is only 18 miles from Zizers, she did not visit the country for 63 years. An Austrian law, enacted after the revolution in 1919, allowed entry only to those members of the Hapsburg family who pledged allegiance to the Austrian republic.

All but Zita signed the pledge. ''My mother felt that abdication would have amounted to a betrayal of my father,'' Otto explained.

In 1982, Austria relaxed the ban following a personal request by Spain's King Juan Carlos, a relative of Zita. Thousands cheered when Zita appeared at St. Stephen's Cathedral.