Indonesian women's groups have welcomed the passage of a bill which ensures that 30% of all candidates in next year's parliamentary election will be female.
Indonesian women are ready to play a more active role in politics
The measure could make a big difference to a parliament where only 45 of the 462 members are women, despite the fact that President Megawati Sukarnoputri is female.
Ironically, President Megawati's PDI-P party initially opposed the bill, but went along with it after being outnumbered by other parties.
The clause was passed late on Tuesday night as part of electoral changes ahead of next year's general election.
Professor Saparinah Sadli, a psychologist and women's rights activist, told BBC News Online that the result was a great victory for Indonesian women.
Electoral reform bill
Women to make up 30% of parliamentary candidates in 2004 general election
Political parties which fail to gain 2% of vote will not be able to stand in next election
Government officials allowed to campaign for political parties but not using state facilities
"I am particularly glad that they decided to put the figure of 30% to the quota, and didn't just make vague commitments to affirmative action," she said.
However she warned that there had to be the political will to make sure that enough suitable women came forward to stand for parliament in 2004.
President Megawati was herself initially barred from the presidency on the grounds that a woman should not lead a Muslim nation.
"Without such requirements, women will be sidelined in our political life," said Azyumardi Azra, chancellor of the State Institute on Islam.
Megawati is Indonesia's first female president
"This is not discrimination against men or favouritism, it should be understood as a necessity," she told the AFP news agency.
Parliament will soon debate another electoral bill on the holding of the first direct presidential elections next year.
Correspondents say that following decades of authoritarian rule and political instability in Indonesia, the passage of such bills is strengthening the country's democractic institutions.