"Mrs. Arroyo has this penchant for seeing ghosts of the opposition where none exist," Estrada said through his spokesman Didagen Dilangalen.
Estrada said Mrs. Arroyo "should be blaming herself and her administration" for the scandals instead of the opposition.
"She keeps blaming the opposition for every scandal that comes her way. She should start looking in her own backyard to see where the scandals are coming from — and not at the opposition," he said.
"Mrs. Arroyo sounds like a broken record with her claims of the opposition’s attempts to destabilize her government," Estrada said.
At the start of the Senate inquiry last Monday, self-confessed jueteng operator Wilfredo Mayor alleged he regularly gave bribes to Mrs. Arroyo’s son, Pampanga Rep. Juan Miguel Arroyo, three other congressmen, national police chief Arturo Lomibao and several other government and police officials.
Arroyo and the other officials strongly denied the charges.
Earlier, First Gentleman Jose Miguel Arroyo was likewise linked to jueteng operators.
"If her husband and son are innocent of the charges as she claims, Mrs. Arroyo should not be afraid of the truth that may emerge though the testimonies of these witnesses," Estrada said.
Estrada is on trial for allegedly running an illegal gambling protection racket and amassing millions of pesos in bribes from jueteng operators.
He was ousted by a military-backed popular uprising in 2001 following allegations of massive corruption during his 31-month presidency.
Estrada was replaced by then vice president Arroyo. He denies the corruption charges and maintains his ouster was illegal. He claims the trial is rigged.
He is detained at his sprawling rest house in Tanay, Rizal.
Mrs. Arroyo’s government routinely warns of destabilization plots, most recently that the Estrada camp would seek to capitalize on crowds of workers marching during annual Labor Day rallies. Estrada denies the accusation.
Estrada’s movements were restricted recently following intelligence reports alleging that the former president had been providing "logistical support" to a fresh destabilization attempt against the government.
Estrada also scored Justice Secretary Raul Gonzalez for immediately accusing Mayor of lying to the Senate inquiry instead of first investigating Mayor’s claims and encouraging potential whistle-blowers to surface.
"Neither my press secretary nor my justice secretary issued threats of filing suits against anyone who testified against me," Estrada recalled. "The office of the President was never utilized to intimidate and cow the alleged whistle-blowers into submission, to stop them from testifying, because this is an abuse of government power and I knew the truth would come out eventually."
Gonzalez heads a task force that is investigating the allegations against Mrs. Arroyo’s husband and son.
Senate President Franklin Drilon said Gonzalez should inhibit himself from the task force and be replaced by chief state prosecutor Jovencito Zuño.
"How can he conduct an impartial investigation when he had already declared that the witness, Mr. Mayor, was lying to the Senate and could be charged criminally in court?" Drilon asked.
"For opening his mouth too soon, I am afraid Secretary Gonzalez has deprived himself of the public perception that he can be an impartial investigator in this highly-sensitive and emotional controversy."
Drilon added that Gonzalez should stop intimidating witnesses. — With Marvin Sy