Philippine police escort Leila de Lima, a senator detained on drug charges, on her way to a local court to face an obstruction of justice complaint in Quezon city, metro Manila
Philippine police escort Leila de Lima, a senator detained on drug charges, on her way to a local court to face an obstruction of justice complaint in Quezon city, metro Manila, Philippines March 13, 2017. Reuters

A Philippine court on Wednesday rejected a bail request by an ex-senator and chief critic of former President Rodrigo Duterte, prolonging her six years of detention on drugs charges that she insists were baseless and politically motivated.

Leila de Lima, 63, was hit by a slew of charges in 2017 within months of launching a Senate inquiry into Duterte's bloody "war on drugs", during which thousands of users and dealers were killed by police or in mysterious circumstances.

The popular Duterte, whose term ended last year, accused her of colluding while justice minister with drugs gangs in jails, which led to charges of conspiracy to trade narcotics.

Duterte humiliated her in public speeches with lurid revelations about her private life, prompting hate campaigns orchestrated by his cult-like social media following.

Two of three cases against De Lima have been dismissed and De Lima sought bail in the one pending case on health grounds.

"We did not expect this decision," her legal counsel Filibon Tacardon said in a statement, adding a motion of reconsideration would be filed.

"We will continue to fight for justice and the freedom of Senator De Lima after more than six years in detainment and separation from her loved ones."

The court in its ruling said her request was untenable and evidence would determine her culpability or innocence.

Many activists consider De Lima a political prisoner and demand her release. Human Rights Watch said the bail denial "prolongs the injustice committed against her".

"This is a sad day for her and for those who believe in the cause of human rights," it said.

The courts should rule based on merit, and not political influence, the progressive parliamentary group, Akbayan partylist said in a statement.

Duterte was president from 2016 to 2022 and gained international notoriety for delivering on a campaign promise that thousands of Filipinos drug dealers and users would be killed. His daughter, Sara Duterte-Carpio is currently vice president.

The International Criminal Court in The Hague is investigating allegations that crimes against humanity were committed under Duterte's leadership during the drugs crackdown.

He denies inciting police to kill and says he only authorised use of self-defence.

Justice Secretary Jesus Crispin Remulla on Wednesday told reporters the court's decision on De Lima's bail must be respected.