Efforts by Indonesia's Speaker of Parliament, Mr Setya Novanto, to avoid answering in the face of mounting evidence against him in a multimillion-dollar corruption probe may be nearing an end.

In July, the Corruption Eradication Commission (KPK) named him a suspect in the embezzlement of some 2.3 trillion rupiah (S$232.5 million) from the state's coffers more than seven years ago.

Mr Setya failed to show up to answer questions at the KPK twice - on Sept 11 and again on Sept 18 - citing a heart ailment.

Next week, the KPK plans to summon him again, after a doctor declared on Wednesday that the Golkar Party chief's health condition has improved, KPK spokesman Febri Diansyah said, after visiting him and his doctor at the Premier Hospital in East Jakarta.

"The bottom line is that, according to the doctor, the questioning (of Mr Setya) can now be carried out," Mr Febri told Kompas news.

If he fails to show up, the KPK will exercise its powers and forcibly bring him in for interrogation, said independent lawyer Sylvester Riza.

"If Setya Novanto is healthy, he has no excuse to again avoid interrogation," another independent lawyer, Mr Adhi Faiz, said.

Not only has the businessman-politician ignored the commission's summons for questioning thus far, but he also took the KPK to court earlier this month to challenge the legality of its decision to call him a suspect in the 2010 case.

Observers say Mr Setya was flexing his "political muscle" in hopes that the South Jakarta District Court would order the KPK to drop its investigation, even though many of the more than 80 witnesses questioned have already testified against him in separate ongoing hearings involving other defendants in the case.

The investigation revolves around the embezzlement of nearly half of the 5.9 trillion rupiah that Parliament had approved for a national project to implement an e-KTP system, or kartu tanda penduduk - an identity card that was supposed to be issued to Indonesians aged 17 and older in 2009.

The KPK started investigating the project in 2014, saying it could be the largest graft scandal in Indonesia's history.

At least 37 high-profile Members of Parliament are said to have received millions of dollars in kickbacks from deals linked to the supply of e-KTP.

The House Speaker is among six individuals and the third lawmaker identified by the commission as suspects.

The others are Home Affairs Ministry senior officials Irman and Sugiharto, businessman Andi Agustinus, and lawmakers Markus Nari and Miryam S. Haryani.

In July, Irman and Sugiharto were sentenced to prison terms of seven and five years, and fined 500 million rupiah and 400 million rupiah, respectively, after being found guilty of graft. Both men are appealing.

Just days before Irman and Sugiharto were sentenced, the KPK named Mr Setya as a suspect in the case, a bold move against the House Speaker who, as Golkar chairman, wields considerable political influence.

Until then, he had avoided being prosecuted or even named as a suspect in earlier legal tangles, earning him the nickname of "Teflon" don, because nothing stuck when it came to criminal or graft charges, said some analysts.

In 1999, Mr Setya avoided prosecution over the Bank Bali scandal that involved a high-profile, illegal lobbying case to save the then ailing bank, and more recently in the Freeport debacle, where he was heard on tape allegedly demanding kickbacks from the American mining firm last year.

And he was alleged to have had a role in the illegal importation of 60,000 tonnes of rice from Vietnam, also in 2010.

In 2012, the KPK raided Mr Setya's office in the Parliament building in search of evidence of corruption in projects linked to the Riau national sports games.

Riau governor Rusli Zainal was jailed for 14 years, but investigators did not find enough evidence to implicate Mr Setya.

This time though, he may have run out of luck.

"The era has now changed, with public pressure for a more transparent and objective prosecution process having grown in the past years," Mr Adhi told The Straits Times.

"Everyone is now watching. It will no longer be easy for Setya Novanto."