Former President Megawati Sukarnoputri says she is "bitter" about the Nunun Nurbaeti corruption scandal, alleging the case had been politicized to target the Indonesian Democratic Party of Struggle (PDI-P).

Megawati, chairwoman of the opposition party, said the case – which has seen a number of former PDI-P legislators jailed over the affair that highlighted widespread corruption in the House of Representatives (DPR) – had been a "very bitter, very bitter, very bitter experience."

"It has been incredibly politicized," Megawati said at the party's national working meeting in Bandung, West Java, on Monday. "It has been treated differently compared to the Bank Century case, and the election, judicial and tax mafia, and others."

Megawati and the once high-flying PDI-P were hammered by incumbent President Susilo Bambang Yudhoyono and the Democratic Party in the 2009 elections and have struggled to have any real meaningful impact on Indonesian politics since.

In June, sitting PDI-P legislator Panda Nababan was the last of 28 current or former legislators to be convicted and jailed for receiving between Rp 350 million and Rp 1.4 billion each to appoint economist Miranda Goeltom to a senior post at the central bank in 2004.

The politicians were from the PDI-P, Golkar Party, United Development Party (PPP) or the now-defunct police and military bloc.

A number of PDI-P legislators, however, have alleged that the money they received was channeled to the party, in particular for Megawati's failed re-election bid.

The KPK has previously summoned the former president to answer questions in relation to the allegations – including from former senior PDI-P legislator Max Moein – though Megawati refused to appear.

Members of the party have previously accused the KPK of targeting opponents of the ruling government.

Megawati, speaking on Monday, urged the people to support Yudhoyono and Vice President Boediono to uphold the law without prejudice. She said PDI-P lawmakers convicted in relation to the case were "smoke," while investigators had so far proven incapable of finding the "fire," or source of the corruption.

"I'm talking to you, the people," Megawati said. "Is this the way of legal enforcement in Indonesia? "The fire is clear... In Indonesia... law enforcement is still selective."

Nunun has been accused of distributing 480 travelers' checks to 39 former and sitting members of the DPR. The Financial Transactions Report and Analysis Center (PPATK) traced the checks to discover they were purchased from Bank International Indonesia by First Mujur Plantation and Industry, a palm oil firm owned by tycoon Tommy Winata.

Megawati said that regardless of the situation, the PDI-P would not seek revenge if the it won the elections in 2014. "Our morality does not recognize revenge," she claimed. "If PDI-P is trusted in 2014, there is no other option but to uphold discipline in the party not to breach the law. That is better."

The PDI-P lost out in the 2004 elections due in part to the government's inability to contain rampant corruption and the weak leadership style of Megawati, whose family's personal wealth ballooned during her time in office.

Nunun is currently being questioned at KPK headquarters in South Jakarta. KPK deputy chairman Bibit Samad Riyanto said they would seek a second opinion regarding Nunun's alleged medical condition that causes memory loss.