Jakarta :  Indonesian opposition politicians welcomed on Thursday Finance Minister Sri Mulyani Indrawati's decision to quit, a sign the country faces a prolonged fight over reform seen as crucial to luring investment and spurring growth.

While investors and reformers now face uncertainty over the pace of reform, some opposition politicians stepped up criticism of Indrawati, adding they hoped her fellow reformer, Vice-President Boediono, was next in line to quit.

President Susilo Bambang Yudhoyono won a second five-year term last year on promises to continue the fight against corruption and drive economic growth.

With the presence of reformers such as Indrawati in his cabinet, investors have poured money into Indonesian assets on expectations of strong economic growth and improved prospects of an investment grade credit rating for this G-20 member.

Stocks tumbled nearly 4 per cent on Wednesday and continued to drop on Thursday, while the rupiah weakened to 9,225 per dollar on Thursday, from 9,030 on Wednesday following the announcement Indrawati would join the World Bank as a managing director.

But economists said the sell-off was mainly a reflection of investor jitters over euro zone woes, rather than a reaction to Indrawati's departure from the financial driving seat in Southeast Asia's biggest economy.

Indrawati, a respected economist and former IMF director who has pushed civil service reform and taken a tough stance on corruption, has made many enemies among Indonesia's political and business elite during her time as finance minister.

Her clean-up of the notoriously corrupt tax and customs offices has hit powerful vested interests ranging from the businessmen and law-enforcement officials who benefited from smuggling goods to tycoons who routinely evaded paying millions of dollars in taxes and duties.

Over the past 18 months, Indrawati and fellow reformer Vice-President Boediono have come under attack from political opponents eager to unseat two of the most powerful drivers of change in Indonesia, in particular for their role in approving a bank bailout.

Indrawati and Boediono, the former central bank governor, agreed to the bailout of a small lender, Bank Century, at the height of the 2008-2009 global financial crisis to stave off the risk of widespread panic in Indonesia's financial markets.

Both faced months of questioning and highly politicised criticism and grandstanding by parliamentarians.

The investigation failed to find any evidence of corruption by either, and President Yudhoyono publicly backed Indrawati and Boediono, but parliamentarians continue to attack both.

Fuad Bawazier, a senior member of the opposition Hanura Party, told local media he believed Indrawati's departure is in line with the recommendations made by the Bank Century inquiry committee.

"I hope Boediono is next," he told Republika.

Akbar Faizal, another member of Hanura critical of Indrawati, told Reuters both Indrawati and Boediono had been "a big problem" for Indonesia because of the bailout.

Separately, he told local media Indrawati should be banned from travelling overseas to take up her post at the World Bank because she still has a pending criminal case in the country.