MANILA — The Philippines’ highest court on Friday forced out its chief justice, removing a fierce critic of President Rodrigo Duterte and his brutal war against drugs, which has left thousands dead.

Voting 8-6, the Supreme Court justices removed Chief Justice Maria Lourdes Sereno, approving a petition filed by the government’s lawyer that questioned the validity of her appointment on the ground that she had failed to fully disclose her wealth.

Ms. Sereno has been a constant irritant to the increasingly autocratic rule of Mr. Duterte, questioning the validity of his list of public officials deemed to be drug suspects and opposing his declaration of martial law in the southern Philippines.

Senator Risa Hontiveros, a supporter of Ms. Sereno, said the court had surrendered its judicial independence and integrity by removing the chief justice.