MANILA - Former president Benigno Aquino III and his former budget secretary on Monday faced a House investigation into their administration's deployment of a dengue vaccine that is now at the center of a health scare.

The House good government and public accountability committee will ask Aquino and ex-budget chief Butch Abad on the legality of their move to realign P3.5 billion in savings to buy Dengvaxia, said Surigao Del Sur Rep. Johnny Pimentel, who is leading the inquiry.

The Dengvaxia manufacturer, France's Sanofi-Pasteur, admitted late last year that the drug could cause more severe symptoms when given to those who have not had the mosquito-borne disease. This prompted the government to recall the drug.

Under the law, savings may only be realigned for projects that are within the same allotment class, unless authorized by the president, Pimentel noted.

• Why use savings for Dengvaxia program? Aquino explains

Aquino, Abad, and former executive secretary Paquito Ochoa, Jr. faced an earlier hearing at the Senate and denied rushing the procurement of the vaccine.

• 'To protect the people': Aquino defends decision on Dengvaxia use

Some 830,000 public school students received Dengvaxia in Metro Manila and the surrounding Central Luzon and Calabarzon regions.

Aquino, Abad and 18 Health officials are facing a complaint for allegedly violating the 2016 election ban on government projects when they implemented the immunization campaign.

Separate mass murder, plunder and graft complaints have been lodged before the Office of the Ombudsman against Aquino, Abad, Ochoa and former health secretary Janette Garin over the issue.

Watch a livestreaming of the House hearing here.