Lawyer Leonard de Vera said the order automatically grants clemency to convicts reaching age 70 for humanitarian reasons.
He pointed out that Estrada, who will turn 69 on April 19, will benefit if his five-year trial is still ongoing by the time he reaches age 70.
"The executive order will benefit the former president," De Vera, a former head of the Integrated Bar of the Philippines, told reporters in a forum yesterday.
However, De Vera noted, anti-crime watchdog groups such as the Volunteers Against Crime and Corruption are lobbying against the presidential order.
Estrada was elected by a landslide in 1998, but accusations of graft and corruption hounded his presidency.
An impeachment trial against him was aborted in 2001, and he was then toppled in a military-backed popular uprising following accusations by an estranged drinking buddy that he plundered up to P4 billion during his 31 months in office.
Estrada denies the charges and claims that the trial was rigged. He maintains he was illegally ousted from the presidency and is, therefore, immune from suit.
He claims that he was toppled by a conspiracy among the Catholic Church, high-ranking officers in the military and the wealthy elite.
Prosecutors alleged the former president committed plunder — a non-bailable offense punishable by lethal injection — by amassing about P4 billion in illegal gambling payoffs, tax kickbacks and commissions stashed in secret bank accounts under the alias "Jose Velarde."
Estrada also faces a minor charge of perjury for allegedly underreporting his assets in 1999.
He took the witness stand for the first time last week to dispute accusations that he took huge kickbacks during his aborted presidency and claiming he was framed.
He denied pocketing P130 million of the P200 million in tobacco excise taxes remitted by Ilocos Sur farmers, as alleged by his estranged drinking buddy, Ilocos Sur Gov. Luis "Chavit" Singson, the main prosecution witness.
"These are trumped-up charges, a frame-up," Estrada said during direct examination by his lawyer on the kickback allegations.
Singson had testified in 2002 that Estrada had asked for a 10-percent cut of the P200-million tobacco excise tax that he had released.