"It pains me to write this letter, but the challenge that confronts the nation today goes beyond personal attachments," Guingona, who previously served as Arroyos vice president, said in a letter to her. "We decide as conscience dictates."
Guingona also briefly served as Arroyos foreign secretary, and disagreed with some of her policies especially on giving US troops access to counter-terrorism training grounds in the Philippines.
Earlier yesterday, 10 of Arroyos Cabinet members one-third of the total resigned, and asked her to hand over power to Vice President Noli de Castro.
Guingona did not raise the topic of Arroyos resignation.
Mrs. Arroyo has bolstered relations with China and said cooperation with Beijing was one of the pillars of her foreign policy.
Foreign Secretary Alberto Romulo, who has remained loyal to President Arroyo, said a Chinese delegation headed by Beijings ambassador to the Philippines has expressed support for her administration despite the current crisis. AP, Pia Lee-Brago