Parliament was to decide Monday on a revised state budget that would pave the way for an increase of 44 per cent in petrol prices, from 4,500 rupiah (45 US cents) a litre to 6,500 rupiah.
Students and union activists picketed the parliament building amid heavy rain, shaking the metal gates and shouting slogans.
"The fuel price increase will only hurt the poor because it will always be followed by increases in prices of basic commodities," said Abdi Irfansyah, a student participating in the rally.
Protests were also held in major cities across the country.//DPA