The prime suspect in the massacre of 57 people in the volatile southern Philippines last year pleaded not guilty on Tuesday to multiple counts of murder.

The case against Andal Ampatuan Jnr, a local mayor and a leader of a powerful clan, has thrown the spotlight on the nation's corruption-plagued political and justice systems.

More than 30 heavily-armed police escorts took Ampatuan to a special court inside the national police headquarters for his arraignment and a bail hearing, the first steps in judicial proceedings that many fear could drag on for years.

"Not guilty," Ampatuan Jnr's lawyer Sigfrid Fortun told the court when asked to enter a plea as his client stood beside him.

The judge adjourned the hearing until January 13 after the prosecution asked to present over a dozen witnesses to block Ampatuan's application for bail.

Ampatuan Jnr allegedly led 100 of his men in stopping a convoy carrying supporters of a political rival and journalists in the southern province of Maguindanao on November 23.

The victims were systematically murdered and buried in shallow pits or dumped in grasslands near a highway in Maguindanao, where Amapatuan Jnr's father and namesake was governor.

Those killed in the worst political murders in the Philippines included pregnant women and about 30 journalists.

Ampatuan Jr pleaded not guilty to 41 counts of murder on Tuesday, but is expected to be charged with 57 counts when final death certificates are processed.

'Justice system put to a test'

Ampatuan Snr and several other clan members were arrested after martial law was imposed in Manguindanao and charged with rebellion. No date for their court appearance has been set.

Ramon Casiple, an analyst with the Institute for Political and Economic Reform, said the public must monitor the trial "every step of the way."

"What we are facing here is a very strong clan with very strong political connections and the capability to intimidate or even kill witnesses," he told AFP .

"This puts the justice system to a test, because past cases with heavy political overtones have never been satisfactorily concluded."

Casiple cited the trial of former president Joseph Estrada, who was deposed in a military-backed popular revolt in 2001, for massive corruption.

After a marathon six-year trial, he was convicted and sentenced to life imprisonment, only to be pardoned and set free by his successor Gloria Arroyo.

"At the end of the day, it's still politics talking. And these warlords will not go down quietly," Casiple said.

One judge had already backed out from the explosive case, saying he feared for his life. There have also been calls from prosecutors for the justice department to ensure the safety of witnesses.

In a report to Congress defending martial law, Arroyo said those massacred bore "marks of despicable torture, contempt and outrageous torment."

Relatives of the victims said they hoped for a swift trial, but were also prepared for a drawn out legal battle.

"I believe we will get a speedy trial," said Myrna Reblando, whose husband Alejandro was among the journalists slain. "Those of us who are left behind, however, are prepared to fight for justice however long it may take."

Executive support for armed militia

Ampatuan Snr had controlled Maguindanao province for most of the past decade and was grooming his son to take his place as governor in national elections in May.

Ampatuan Snr's influence and power grew because Arroyo allowed him to maintain a 3,000-strong heavily armed militia as part of a government strategy to contain Muslim separatist insurgents in the south.

In exchange for the support, Ampatuan also helped deliver votes from the province to Arroyo and her candidates in the 2004 election allegedly through cheating.

The shocking crime forced her to cut political ties with the clan, but critics say the Ampatuans may still hold enough political power to avoid the penalties many believe they deserve.

- AFP