MANILA - The Supreme Court junked former Senator Ferdinand "Bongbong" Marcos Jr.'s petition that seeks to inhibit a magistrate he accused of being "biased" on his poll protest against Vice President Leni Robredo.

Marcos, in his plea, wanted Associate Justice Benjamin Caguioa to inhibit from his poll protest, saying he "cannot deny that he is biased" towards allies of his "friend" and "former boss," former President Benigno 'Noynoy' Aquino III.

In its decision released on Monday, the high court issued a "stern warning" against the former senator that any unfounded and inappropriate accusation will be dealt with in the future with more severity.

"A justice cannot withdraw from a case as a matter of convenience or as a means to avoid controversy," the Supreme Court, sitting as the Presidential Electoral Tribunal, added in its ruling.

• Marcos slams 'biased' SC justice, seeks inhibition in poll protest

Aquino appointed Caguioa, his former classmate at the Ateneo de Manila University, to the Supreme Court in January 2016. He was Aquino's ad interim justice secretary in 2015 after Leila de Lima vacated the post to run for a Senate seat.

Marcos filed a poll protest against Robredo after losing by about 260,000 votes in the 2016 elections.--report from Ina Reformina, ABS-CBN News