Metro Manila (CNN Philippines, May 7) — Supreme Court (SC) Associate Justice Teresita de Castro has been nominated as Ombudsman to replace Conchita Carpio-Morales, who is set to retire in July after her seven-year tenure.

Retired SC Justice Arturo Brion nominated De Castro to the post, citing her 45 years in government service.

De Castro has been vocal in her support for the ouster of Chief Justice Maria Lourdes Sereno.

The government's top lawyer, Solicitor General Jose Calida, has filed a quo warranto case against Sereno before the Supreme Court questioning her right to hold office. President Rodrigo Duterte himself has branded Sereno his enemy and called for her ouster from the Supreme Court, urging the House of Representatives to speed up a pending impeachment case against her.

"Through all these years, she has served the government with competence, probity, and integrity," Brion said of de Castro in his two-page letter to the Judicial and Bar Council dated May 3.

"Her long years in the prosecutorial service (almost 19 years) and in the Sandiganbayan (more than 10 years), not to mention her more than a decade of experience as an Associate Justice of the Supreme Court, fully qualify her for the position of Ombudsman," he added.

De Castro, who will retire from the SC in October, has yet to accept the nomination -- a requirement for the JBC to consider her for the post.

De Castro began her government service at the SC Office of the Clerk of Court in 1973. She then served at the Justice Department from 1978 to 1997.

She became an Associate Justice of the Sandiganbayan in 1997, and became its Presiding Justice in 2004. In 2007, she was appointed as SC Associate Justice.

Sereno and De Castro figured in a heated exchange last month during the SC oral arguments on the quo warranto petition against the chief magistrate.

The quo warranto is a legal proceeding where an individual's right to hold office is challenged. Calida wants the SC to void Sereno's appointment as chief justice for her alleged failure to file Statements of Assets, Liabilities, and Net worth for 10 years, before she applied for the Chief Justice post in 2012.

De Castro was also among the five SC justices who testified in the House Justice Committee's hearings on the impeachment charges against Sereno.

Application for the Ombudsman post is open until May 15, after being extended from the original May 2 deadline.