On this Caribbean island where traditional loyalty binds voters to one of the two dominant political parties as blood binds father to son and where politics is a passion that often leads to gunfights in the slums, there is a much-savored irony that a popular former prime minister could be reborn politically using one of the tricks of the man who ousted him.

In January 1979, and again last week, thousands of Jamaicans, most of them young and poor, took to the streets at dawn the day after the government announced an increase in the price of oil.

They built roadblocks with junked cars, rusted refrigerators, old tires, tree trunks and tons of empty bottles. Then they set the roadblocks afire. Jamaica ground to a brief but agonized halt, and American tourists nervously called their travel agents.

The prime minister accuses the opposition leader of subverting the government for calculated political purposes, while the opposition leader accuses the prime minister of callous indifference to the people. Both sides deny responsibility for violence and blame the foreign press for scaring away tourists. A new political season is under way.

In 1979, it was Edward Seaga, then the opposition leader, who used a government-imposed oil-price increase to mobilize support for a successful challenge to Michael Manley, who was then prime minister.

Last week, when Prime Minister Seaga announced a 21 percent increase in oil prices, opposition leader Manley's party seized the opportunity to condemn the move and help organize a two-day-long "robust demonstration" -- no one here uses the word "riot" -- that closed businesses and schools, frightened many tourists and led to the deaths of seven Jamaicans.

"Let me just say it is a very interesting coincidence," Rex Nettleford, a prominent Jamaican sociologist, said. "At the very least, the disturbances mean the people are ready to be organized."

After four years in power, during which Seaga has espoused a pro-U.S., free-enterprise line that has made Jamaica a favored recipient of Reagan administration foreign aid, the prime minister's government is swamped by economic problems that appear remarkably similar to those that helped sink Manley. Unemployment is stands at 25.6 percent, inflation is 30 percent a year and the Jamaican dollar is falling in value almost daily.

As Manley did in 1979 and 1980, Seaga is preaching sacrifice and austerity and asking Jamaicans to be patient.

Last week's demonstration, following four years of relative quiescence among Jamaica's large and increasingly impoverished underclass, is widely interpreted here as a sign that patience is running out.

When the roadblocks appeared Jan. 15, a young woman called Jamaica's most listened to radio talk show, "The Public Eye," to sound a lament that pollsters and political observers agree is becoming increasingly common in the Kingston slums.

"Ninety-five percent of us are nothing. And so we have nothing to lose," the woman said, in support of the roadblocks.

Jamaica, the largest English-speaking island in the Caribbean, is a young, poor and urban society. Nearly 40 percent of the nation's 2.3 million people are under 15 years old. About 60 percent of the island's population is concentrated in five cities. The estimated per capita income in Jamaica last year was $932.

"A lot of young people have a sense of hopelessness, no sense of place, no sense of purpose," sociologist Nettleford said.

In the last contested national election campaign here, a nine-month-long affair in 1980 that cost more than 500 lives, roadblocks and rifle fire became a mainstay of politics in Kingston's slums. Nearly five years later, the slums remain riven by loyalties to either Manley's People's National Party or Seaga's Jamaica Labor Party.

What remains to be seen is whether the economic squeeze, which has tripled the price of most necessities during Seaga's term, will force another election.

Seaga, in an interview Friday, said no. "A call for elections now is not something that is going to receive more than just plain partisan, fanatical backing. It will peter itself out."

Manley said that without an election the government will never "inspire the unity and commitments necessary to rescue the nation from the perilous position in which it is now placed."

Recent polls show Manley's party with a commanding lead in popular opinion over Seaga's party, 38 to 26 percent, with 34 percent undecided. Under Jamaica's constitution, which mandates a national election at least every five years, Seaga is not obliged to call an election until the end of 1988.

Following the 1983 U.S. invasion of Grenada, which Seaga praised throughout the Caribbean as a blow to Cuban President Fidel Castro and to communism, the prime minister capitalized on a brief spurt in his popularity and on disarray in Manley's party to win a second term. Manley's party boycotted the election.

Although Seaga theoretically does not have to worry about Manley until 1988, the volatility of the hard-pressed Jamaican electorate and a profound difference in the personal political appeal of the two party leaders are forcing him to remain wary of Manley.

Seaga is viewed by many Jamaicans as a dull person compared to Manley. Boston-born and Harvard-educated, Seaga has the patrician manner and box-office appeal of a bank president. He peppers his speeches with percentages and number-based reasons why Jamaicans should be willing to continue to sacrifice now for the long-term success of his financial program.

"Seaga is one of the most uncharismatic of politicians," said Orlando Patterson, a Jamaican sociologist who now teaches at Harvard. "He was voted in not because Jamaicans liked him, but because he claimed he would be able to manage the economy better than Manley."

For a variety of reasons, many of them beyond Seaga's control, the prime minister thus far has not revivified the Jamaican economy. So, with last week's island-wide disturbances as a symbol of widespread discontent, Manley is seen to have an opening.

A silver-haired orator, handsome and athletic, Manley specializes in fiery speeches about Jamaica's front-line status in a new Third World order. Even after eight years of his socialist policies had pushed Jamaica to the brink of bankruptcy and scared away approximately 30 percent of the island's professional and managerial class, Manley continued to have an appeal to poor Jamaicans.

Now Manley has launched a campaign to force Seaga to call an election.

Whatever Manley's chance of success -- and most observers here see an election as unlikely this year -- the gas-price demonstrations indicate that Jamaicans are unwilling to suffer quietly and are ripe for the island's brand of politics.

"The violence clearly shows that the old spark is not dead," Nettleford said. "The battle fatigue is over."