Thousands of people rallied in Indonesia's biggest cities on Tuesday, seeking to pile pressure on the government to reverse its first subsidised fuel price hike in eight years amid soaring inflation.

Under pressure to control a ballooning energy subsidy budget, President Joko Widodo on Saturday said he had little choice but to hike subsidised fuel prices by about 30%, an unpopular move in the country of 270 million people. Oil prices are about 32% higher than a year ago.

By midday on Tuesday, protests were underway in and around the capital Jakarta and in the cities of Surabaya, Makassar, Kendari, Aceh, and Yogyakarta, among a series of demonstrations led by students and labour unions that police say could draw tens of thousands of people this week.

Thousands of police were deployed across Jakarta, many guarding gas stations, fearing those could become targets of mounting anger over a price hike that unions say will hurt workers and the urban poor the most.

"Workers are really, really suffering right now," said Abdul Aris, a union official.

"The price shouldn't have been raised," he said, vowing to keep fighting until the government gives way.

Tuesday's protests started peacefully, with no early reports of violence or arrests.

Thousands gathered in Jakarta wearing red or orange bandanas, marching and chanting slogans denouncing the government move and calling for an increase in the minimum wage.

One demonstrator was seen shirtless with feet shackled to an empty petrol tank, carrying a sign highlighting hardships of rising costs.

Textiles factory worker Adi Asmadi, 29, said his daily transportation expenses would go up sharply.

"If the fuel price is hiked and wages increase too, that's ok," he said. "If it's not, we object."

Subsidised fuel is a sensitive issue in Southeast Asia's second-biggest economy, but the government has sought to soften the blow through compensation measures, including direct cash transfers.

The hike would cut subsidy spending by about 48 trillion rupiah ($3.22 billion) this year to 650 trillion rupiah, a deputy finance minister said on Monday, but it would also see inflation accelerate.

Small rallies took place at the weekend and on Monday, with tyres burned and some roads blocked as demonstrators vented their anger over the decision, which comes amid rising food costs and with the economy still reeling from the impacts of the pandemic.