Sir Robert Menzies, 83, prime minister of Australia for 19 years and a dominant force in his country's modern development, died yesterday at his home in Melbourne.

The cause of death was not disclosed, but Menzies had been confined to a wheelchair since suffering a stroke in 1975.

He served as prime minister at the head of a coalition government from 1939 to 1941 in the early years of World War I. He headed the government again from 1949 to 1966, when he retired. He was prime minister longer than any other figure in Australian history.

He presided over Australia's post-war prosperity.While maintaining close ties with Britain, he strengthened his country's economic and defense ties with the United States and sent a battalion of Australian troops to support the U.S. effort in Vietnam. He founded the Liberal Party, which has been in power in Australia for 25 of the past 28 years. He often was compared to his friend, the late Sir Winston Churchill.

Queen Elizabeth II of Britain, another friend, sent a message of condolence to Dame Pattie, Menzies' wife. Malcolm Fraser a protege of Menzies and the present prime minister of Australia, said: "All Australians will mourn his passing. He gave his party and his country inspiration."

Bill Haydon, the leader of the opposition Labor Party, said Menzies had been "a master parliamentarian and political tactician.

"He created the federal Liberal Party from the fragmented conservative forces of the '40s and welded together a cohesive coalition which he dominated during a record term as prime minister."

In Washington, President Carter said that in the death of Menzies, "the United States has lost a firm friend and Australia a great leader. After his retirement from public life, he continued to work at strengthening the ties of friendship that bind our countries, serving for a year as scholar-in-residence at the University of Virginia."

At six-feet-two, Menzies was an imposing figure. His full head of white hair and his bushy black eyebrows were a pleasure to cartoonists. He was a conservative in politics, a lawyer and noted constitutional expert by training, a conversationalist of wit and charm, an orator, a lover of good food and wine, and an ardent cricket fan. He was contemptuous of the press. Socialism, and the United Nations. His trade union opponents called him "Pig Iron Bob."

He also had command of an acid tongue. When it was suggested to him that he looked down on others, he replied. "Considering the company I keep in this place, that is hardly surprising."

He once told a woman heckler, "Madam, I do not know your husband, but he has my profound sympathy."

On another occasion he described himself as "a reasonably bigoted descendent of the Scottish race."

So strong was his attachment to the British Crown that in 1967, when Australia changed its currency to the decimal system, he suggested that the basic unit be called "the royal." The idea was not adopted and the term "dollar" was introduced instead.

When he retired from politics in 1966, Menzies said he was tired and that his pace had slowed. "At 71, one becomes not quite 100 percent in efficiency," he said. "I have an old-fashioned belief that prime ministers of this country should be 100 percent efficient at all times."

After spending a year as scholar-in-residence at the University of Virginia, Menzies returned to Melbourne to write his memoirs. In them mme cited three occassions on which he tried and failed to influence world politics.

The first was his warning to Britain and the United States in 1941 that the Japanese were bent on a course of aggression in Asia. The second was in 1956, when he tried to mediate the Suez dispute between Egypt and Britain and France. The third was in 1961, when he tried to keep South Africa in the British Commonwealth by appealing to the South African government to moderate its policies of total racial separation.

In 1971, the publication of the Pentagon Papers forced Menzies to defend his controversial decision to send Australian troops to Vietnam and to defend his personal integrity as well. The Pentagon Papers suggested that the United States had prompted the action. Menzies had maintained that at the time he took the decision he was acting on a direct request from the Saigon government. He repeated that position in 1971.

Robert Gordon Menzies was born at Jeparit, small town in the state of Victoria in southeastern Australia. His father was a shopkeeper and the young Menzies got his education through scholarships. He was a brilliant student at Melbourne University and became a lawyer at the age of 24. By the end of the 1920s, he was making more than $30,000 a year, a large sum at that time.

He entered politics in 1928 as a member of the Victoria state legislature. He was elected to the national parliament in 1934 and became attorney general. He was made prime minister of a coalition govenment at the outbreak of World War II. One reason he was forced to resign was the fact that he had not served in World war I, in which Australia had 60,000 killed. He said that his family had decided that his brothers should go into the Army but that he should remain at home.

After 1941, he became the leader of the opposition and began to form the Liberal-Country Party, which came into power in 1948.

In 1963, Menzies was created a knight of the Order of the Thistle, the highest order of Scottish knighthood, by Queen Elizabeth. After his resignation in 1966, Queen Elizabeth made him Lord Warden of the Cinque Ports, an honorary post whose origins lie in the Middle Ages and which Sir Winston Churchill had held before him.

In 1920, Menzies married Pattle Leckie, the daughter of an Australian senator. They had two sons, one of whom died, and a daughter.