MANILA - Chief Justice Maria Lourdes Sereno accused the Office of the Solicitor General (OSG) of forum shopping as she asked the Supreme Court anew to junk the quo warranto petition against her.

Forum shopping is a prohibited malpractice of looking for a court or judge that is deemed likely to render a favorable result.

The issue raised in the quo warranto petition and the separate articles of impeachment earlier approved by the House justice committee are “not only related, but identical,” Sereno said in a supplemental memorandum filed by her camp last Friday.

The quo warranto and impeachment cases both sought Sereno's removal from office over her failure to file her statement of assets, liability and net worth (SALN) as a University of the Philippines professor.

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“The OSG has committed willful and deliberate forum shopping, which should result in the outright dismissal of the quo warranto petition,” Sereno said.

“The forum-shopping in this case was willful and deliberate even though it was well-aware of the identical issues, subject matter, and relief sought in the impeachment proceeding,” she added.

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The top magistrate also questioned why Speaker Pantaleon Alvarez supported the simultaneous hearings of the the impeachment and quo warranto cases.

“The answer is plain: Those behind the impeachment before Congress and the Petition before this Honorable Court are one and the same,” Sereno said.

Sereno, in her petition, also alleged that some members of the High Court are "prejudiced" in the ouster bids against her.

The Chief Justice in April moved for the inhibition of Associate Justices Teresita Leonardo de Castro, Diosdado Peralta, Lucas Bersamin, Francis Jardeleza, and Noel Tijam from the quo warranto case.

The magistrates had testified against Sereno in the impeachment proceeding and participated in the so-called “Red Monday” protest that demanded her resignation.

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In her supplemental memo, Sereno made her final appeal to her colleagues in the High Court to think over the implications of their decision, “not only on the independence of the judiciary, but also on the political structure carefully designed by the Filipino people and enshrined fundamental law.”

Judgment in the case, she said, will decide the fate of incumbent and future members of the Supreme Court.

“The Chief Justice thus humbly renews her call on her brethren in the Supreme Court to remain faithful to their oaths to uphold and defend the Constitution, applicable law and jurisprudence, keeping in mind the utmost necessity of safeguarding the separation of powers and the system of checks and balances firmly ingrained therein,” the supplemental memo reads.

It was earlier reported that the high court may decide on the case on May 11.

The country's first female chief justice has been on leave from her duties at the Supreme Court since March in preparation for her impending impeachment trial. She was expected to stay in her post until she reaches the mandatory retirement age in 2030.