As the Indonesian government prepares to raise fuel prices next month by as much as 50 percent, Kasum, a veteran taxi driver, frets about continuing the work he has done since he was 12 years old.

"Given fuel prices today, it's already hard to get enough money to pay my family's rent," said Kasum, 40, his brow baked by years up front in a three-wheel bajaj cab. "I don't know what will happen if the prices go up again."

Facing record-high world oil prices, President Susilo Bambang Yudhoyono has announced plans to slash government subsidies and raise prices for kerosene and fuel on Saturday. Indonesians now pay the equivalent of about 90 cents a gallon for gasoline, among the lowest prices in the world.

In advance of the higher prices, officials said Wednesday that they would deploy 5,500 police in Jakarta, the capital, expecting anti-government demonstrations.

Yudhoyono, elected in a landslide last year, faces the choice of bankrupting the country because of the subsidies, analysts said, or pushing through the kind of price increases that can topple governments. The subsidies account for about one-third of government spending in a country where health, education and other basic services remain severely underfunded. The president has projected that the fuel payout could reach nearly $14 billion a year if left unchecked.

But similar endeavors have proved hazardous for his predecessors. Longtime dictator Suharto was forced from office in 1998 during massive protests sparked by a range of grievances including rising fuel prices. Former president Megawati Sukarnoputri had also sought to boost gasoline prices in 2003 but was forced to backtrack by widespread demonstrations. Her proposal to increase prices for several basic goods undercut her image as a defender of Indonesia's poor, contributing to her election loss.

The steep cost of oil is squeezing governments throughout Southeast Asia. Thailand ended fuel subsidies in July, winning praise from financial analysts but stoking inflation. Malaysia, a net oil exporter, is also raising domestic prices. The Asian Development Bank noted this month that the economy of these two countries, along with those of the Philippines and Singapore, are especially vulnerable if world oil prices remain high.

So too, the soaring expense is taking a toll across much of the rest of Asia and Africa. India, for instance, boosted the price of subsidized fuel this month despite sharp criticism from the government's allies. And in Nigeria, Africa's largest oil producer, thousands of people marched through the capital last week to protest a government move to increase prices of gasoline and diesel by reducing subsidies.

In Indonesia, where subsidies have been especially generous, students have already staged several demonstrations against the planned price increase. The government has not said how much prices will rise, but officials have said they could go up an average of 50 percent.

Kasum is among tens of thousands of bajaj drivers, whose garishly orange three-wheelers maneuver in and out of Jakarta traffic, belching black exhaust. The drivers have scheduled a citywide rally of taxi and bus operators this week. Meanwhile, drivers have been lining up to fill their tanks, anticipating higher prices.

"I thought with this president, fuel prices would not go up so high," said Kasum, who estimated that he spends about $6 a day on gasoline and leasing his vehicle. "But with this new president, everything is getting worse and worse."

Yudhoyono increased fuel prices an average of 29 percent in March. That measure, however, failed to keep pace with the soaring international cost of oil, which top officials said now runs the government more than double what it charges consumers at the pump.

With the government paying dollars to import oil, the Indonesian currency, the rupiah, came under intense pressure last month, losing up to 20 percent of its value against the dollar. In recent weeks, however, the rupiah has strengthened after the central bank raised interest rates and Yudhoyono promised to rein in subsidies.

Faced with mounting turmoil, Yudhoyono postponed a planned trip to the Middle East and headed directly home last week from the U.N. summit in New York to tackle the fuel issue.

The president remains popular, with an approval rating of 64 percent, according to a poll conducted by the Indonesian Survey Institute, and enjoys unprecedented legitimacy as the country's first directly elected leader.

But Ikrar Nusa Bhakti, a political analyst at the Indonesian Institute of Sciences, warned that Yudhoyono is more vulnerable than poll numbers indicate.

"There will be a lot of demonstrations, not only in Jakarta but also in other areas across Indonesia," he said. "They will be not only about fuel prices but also about other economic problems in the country."

Indonesia's agony reflects a reversal of fortunes for an oil-producing country that was long a net exporter and still remains a member of OPEC, although it now imports oil. Domestic demand for cheap gasoline has increased while Indonesia's production has failed to keep pace as foreign investors stay away, intimidated by corruption and a flawed legal system.

This month, Exxon Mobil Corp. signed a 30-year agreement with the national oil company, Pertamina, for joint production in the huge Cepu field off Java island. Government officials said this could lift Indonesia's current daily output of about 1 million barrels of crude oil by about 20 percent, but not until 2008 at the earliest.

Pertamina's white office tower rises from a prime piece of real estate across from the national monument and just south of the national mosque. The building is visible across a murky canal from Pasar Baru market, where Ajo Aliludin runs a food stall.

"This increase is too much for us," lamented Aliludin, 63, a short, sober man with frameless glasses, adding it could drive away business. It was particularly unfortunate, he said, that Yudhoyono was likely to boost the fuel price on the eve of Ramadan, when holiday spending traditionally accelerates.

"His predecessor was better. She never raised the prices this much," he said.

Vuru Heksayanti, 36, a shopper wearing a conservative black headscarf over a green tunic, said she sympathized with Yudhoyono's predicament, suggesting that the swelling budget deficit was the result of inaction by the previous administration. Still, she added, her loyalty would shift to the demonstrators if the government proceeded with a 50 percent increase.

"We understand prices have to go up but not too much," she said. "It can't be so drastic."

Indonesian drivers line up to fill their tanks at a gas station in Yogyakarta, a city in central Java, before fuel prices rise Saturday by as much as 50 percent.A student jumps over a burning tire in southern Sulawesi province during a protest against the planned fuel price increase. Authorities are girding for more protests.