MANILA, Jan 16: A historic impeachment trial of the Philippines' top judge began on Monday in one of President Benigno Aquino's boldest yet most divisive moves to tackle pervasive corruption.

Members of the 23-person Senate gathered as judges to determine whether Supreme Court Chief Justice Renato Corona should be removed from his post and become the highest-profile scalp yet in Mr Aquino's anti-graft crusade.

'Renato Corona by his misdeeds is unfit to remain chief justice,' lead prosecutor Niel Tupas said in his opening address to the hearing, which could last months and see Mr Aquino accused of overstepping constitutional boundaries.

Mr Corona is accused of violating the constitution in his efforts to protect grafttainted former president Gloria Arroyo from prosecution, while also for allegedly amassing a personal fortune above the limits of his salary.

'The prosecution will show how chief justice Corona became the crowning glory of the cast of accomplices of the former president, and how he protected (her) interest in exchange for the position of prestige and power,' Mr Tupas said.

Mr Aquino won a landslide election victory in 2010 on a platform to end corruption which has plagued the Philippines for decades and which he said worsened dramatically during the decade that Ms Arroyo led the country.

Ms Arroyo, 64, was arrested in November on charges of rigging the 2007 senatorial vote and is now awaiting trial in a military hospital where she is being treated for what she says is a rare spinal illness.

President Aquino then marshalled his allies in Congress to impeach Mr Corona, 63, last month, labelling him a 'rogue magistrate' loyal to Ms Arroyo.

Ms Arroyo appointed Mr Corona, her former chief of staff, to the Supreme Court bench in 2002, then to the top judicial post shortly before she stepped down.—AFP