Former Philippine President Gloria Macapagal Arroyo was set to have her fingerprints and mugshot taken at a Manila hospital on Saturday, where she is under police guard after being arrested on charges of electoral fraud.

The order for her arrest was issued by a regional court on Friday afternoon, just before she was scheduled to fly to Singapore after the Supreme Court upheld its earlier suspension of the government's travel ban on Arroyo and her husband.

Her arrest comes 18 months after President Benigno Aquino won an election by vowing to fight corruption and prosecuting those responsible for it, and particularly pursue Arroyo.

I understand that the booking process will be finalised today, Arroyo's legal spokesman, Raul Lambino, told ANC television.

Arroyo says she needs to travel to seek medical treatment for a spine condition, but the government believes she wants to evade investigation and possible prosecution.

Arroyo, president from 2001-2010, has consistently denied the allegations against her.

The alleged vote rigging happened in the restive southern Muslim province of Maguindanao, where all 12 pro-Arroyo senate candidates won a clean of sweep of the province at mid-term elections in 2007, at odds with national trends.

The charges carry a life sentence.

Arroyo also faces allegations of fraud over a 2004 presidential election and corruption in her administration, which the government is still investigating.

Arroyo's predecessor, Joseph Estrada, told local media Arroyo's arrest was karma and he hoped she would recover her health to face the charges.

She should be made accountable not only for electoral sabotage but also corruption, he said from Singapore.

Arroyo took office in 2001 when Estrada was forced from power, and prosecuted him for corruption. In 2007, Estrada was convicted of plunder and sentenced to life imprisonment, but Arroyo pardoned him.

Arroyo has not been seen in public since Tuesday night, when, following the initial Supreme Court decision to lift her travel ban, she had turned up at the airport in a wheelchair and her neck in a brace.

The government stopped her and her husband from boarding a flight, and she has since been in the hospital, where she was formally arrested at 6:30 p.m. on Friday.

On Monday, the Pasay City court that issued her arrest warrant will hear a separate petition to issue a hold departure order, which could permanently prevent Arroyo from leaving the country.

(Reporting by John Mair; Editing by Ed Lane)