JAKARTA -- Indonesia's rapid passage of a revision to a law governing its anti-graft body has sparked concerns that President Joko "Jokowi" Widodo is going soft on fighting the country's endemic corruption.

The House of Representatives, known for its snail-paced deliberations, on Tuesday uncharacteristically passed the amendment to the act on the Corruption Eradication Commission (KPK) after a mere two weeks of debate.

Activists say the revision will weaken the powers of one of the most credible public institutions in a country where the police and parliament are perceived as being widely corrupt.

The Indonesia Corruption Watch says the law was revised to strip the KPK of its law enforcement capabilities and reduce it to an organization focusing merely on prevention. The anti-graft watchdog accuses lawmakers of moving to protect themselves after the agency named 23 sitting members of parliament as suspects in a number of cases.

Anti-graft activists say the law revision lengthens bureaucratic procedures needed for anti-graft investigators to wiretap potential suspects, which they fear will significantly hamper the KPK's law enforcement work. The investigation period into cases will now be restricted to a year, despite past examples showing complex cases often require longer probes.

"This nation is in mourning, dead together," the ICW said on Tuesday, inviting people to attend the "Funeral of the KPK" outside the anti-graft body's headquarters in Jakarta.

Lawmakers passed the revision after Widodo last week permitted deliberations to proceed with only slight tweaks to contentious clauses. The previous week, in an equally controversial move, lawmakers appointed five new KPK commissioners -- some with dubious track records. The incoming chief is suspected of gross ethics violations during his time as a corruption investigator.

Widodo has defended his decision to support the revision, denying claims that he conspired with lawmakers to weaken the KPK. He argued for the need to establish a council to supervise the KPK, but rejected a lawmakers' proposal to appoint the council members. Instead, Widodo said he will appoint the supervisors himself.

"The supervisory council is needed because every state institution -- including the President, the Supreme Court and the House -- needs checks and balances... to minimize the potential abuse of power," Widodo said at a news conference on Friday. "I won't compromise on corruption eradication because corruption is our common enemy."

Josua Pardede, an economist at Bank Permata, a private Indonesian lender, said the revision is unlikely to significantly affect Widodo's development plans, nor will it hurt the country's growth prospects. He noted that the nation's ease of doing business ranking has continued to improve, and that the Widodo government is committed to continually improving the investment climate.

"The government will continue to accelerate development in both physical and nonphysical infrastructure," Pardede said. "The prospects of economy in the long term will remain positive."

However, Dadang Trisasongko, secretary-general of Transparency International Indonesia, warned that the law revision sets a poor precedent for economic reform.

"Weakening the KPK means weakening the agenda to tidy up the business climate and free it from corrupt practices," Trisasongko told the Nikkei Asian Review. "KPK has hitherto being the driver of reforms in the business sector. I'm worried that the president is making a political blunder with this KPK law revision."

Transparency said in an earlier statement that Indonesia still has a lot of work to do to improve its corruption perception index ranking as it remains among the top 30% most corrupt countries in the world, with its CPI score barely improving since Widodo took office in 2014.