The Philippines' Department of Justice says it is opening a formal inquiry into fresh allegations that former President Gloria Arroyo used police to alter vote results from the 2004 presidential election.

Justice Secretary Leila de Lima said the probe will examine claims by a former police superintendent that he and other rogue officers broke into parliament in early 2005 to switch election results stored there. De Lima said the alleged switch was aimed at ensuring that Ms. Arroyo's election win would survive a recount.

De Lima said calculations based on police affidavits (sworn testimony) suggest as many as 1.2 million legitimate election returns may have been replaced with fake ones in the break-ins. Ms. Arroyo won the presidency by 1.1 million votes.

Ms. Arroyo has consistently denied any illegal activities during her 2001-2010 presidency.

The Inquirer newspaper said former senior Police Superintendent Rafael Santiago provided the paper with sealed envelopes from the Philippine Commission on Elections. He said the envelopes contained the original election results.

The newspaper quotes Santiago as saying he acted on orders of then-National Police Director Hermogenes Ebdane. The report says Santiago also implicated a former elections supervisor.

The Arroyo presidency was marked by three military coup attempts between 2003 and 2007 — all of them driven by accusations of vote fraud.