President Rodrigo Duterte dismissed the remarks of Diego Garcia-Sayan and told him in a televised speech early on Sunday not to meddle in domestic problems and "to go to hell".
Sereno's colleagues voted to remove her from office last month, shortly after Duterte openly called her his "enemy" and demanded her swift ouster.
"Tell him (Garcia-Sayan) not to interfere with the affairs of my country. He can go to hell," Duterte told reporters in Manila, insisting he had nothing to do with Sereno's dismissal.
"He is not a special person and I do not recognise his rapporteur title."
The Philippine President reiterated his comment in a video by Inquirer.net.
Duterte, 73, has lashed out in the past -- often using less-than-parliamentary language -- at critics of the deadly drug war he launched soon after coming to power in 2016.
Several of his opponents have since been ousted, punished or threatened.
Police say they have killed 4,279 drug suspects in the anti-narcotics campaign but rights groups believe the actual number is three times higher.
Sereno was one of the few remaining high-profile critics of the crackdown at the time of her ouster.
The UN's Garcia-Sayan said Friday that Duterte's public threats against Sereno appeared to have had a "chilling effect" on her colleagues in the judiciary.
"The use of such derogatory language... sends a clear message to all judges of the Philippines: in the so-called 'war on drugs', you're either with me or against me," Garcia-Sayan said.
Via SBS News
