The trial of a former mayor accused of masterminding the massacre of 57 people in the southern Philippines last November was adjourned again for a week on Wednesday, frustrating state lawyers and families of victims.

Andal Ampatuan Jr's trial on 57 counts of murder over the massacre has been on hold since February as the defence has filed a number of motions that have delayed hearings.

With President Benigno Aquino's two-month-old government heavily criticised for its botched handling of a bus hijacking last week, the case is an important test of his ability to deliver on promises of enforcing the law and improving security.

We're deeply hurt by the delays, said Catherine Nunez, whose son, a television journalist, died in the massacre. We came here hoping to see a trial. But we're disappointed again. They're giving those criminals a lot of chances.

The 57 victims were killed by around 100 armed men as they travelled to watch the filing of papers for a member of a rival clan to stand in elections against Ampatuan, a member of a powerful political clan.

Murder charges have also been brought against Ampatuan's father, uncle and three brothers, who are in custody, and around 190 police officers, soldiers and militia members, about two-thirds of whom are still at large.

The clan had ruled Maguindanao, a province on the southern island of Mindanao, for nearly a decade. It was allied with former president Gloria Macapagal Arroyo, and there was an expectation Aquino would pursue the case more urgently.

Justice in the Philippines is exceptionally slow, Jessica Evans of Human Rights Watch told reporters. Let justice take its course and we'll continue monitoring the trial.

(Reporting by Manny Mogato; Editing by John Mair and Ron Popeski)