The hearings came a day after the main suspect in the case, Andal Ampatuan Jr, was allowed to hold a news conference from jail where he once again professed his innocence.
Ampatuan Jr and his clan, which has dominated provincial politics for over a decade, are accused of carrying out the attack on the convoy of a political rival in what is believed to be country's worst-ever politically-motivated killings.
|Ampatuan Jr's jail press conference sparked criticism from victims' relatives [Reuters]
Among the victims were more than 30 journalists and their staff accompanying the convoy.
Prosecutors believe Ampatuan Jr, his father and two other family members were the key plotters and ring-leaders of the massacre, although as yet no trial date has been set.
On Tuesday, Ampatuan Jr, who is the son of the clan leader, called reporters to a maximum security prison to reiterate his family's innocence.
He also used the news conference to endorse his favoured presidential candidate in next month's national elections.
"I know very well that I am not the perpetrator because I was in my town hall then," the former Maguindanao mayor, told reporters.
"We condemn this in the strongest terms, this is so callous... another indication that we cannot get justice under this administration"
lawyer for slain journalists
Looking relaxed in a yellow prison T-shirt but no handcuffs, he went on to endorse Benigno Aquino Jr, the opposition candidate leading opinion polls ahead of the May 10 presidential elections.
Aquino later shrugged off the endorsement, saying he did not ask for it.
Prison officials said no rules were broken in allowing Ampatuan Jr to hold a press conference from jail, saying detained suspects who had not been convicted had a legal right to speak to the press.
But the press conference sparked condemnation from lawyers and relatives of victims, fuelling accusations that the government of Gloria Macapagal Arroyo, the Philippines president, is favouring the Ampatuan clan.
"We condemn this in the strongest terms, this is so callous," said Harry Roque, a lawyer representing some of the journalists killed in the attack.
"This is another indication that we cannot get justice under this administration."
Al Jazeera's Marga Ortigas reporting from Manila said Tuesday's press conference was being seen by many as indicative of the clan's closeness with the Arroyo administration.
"The families of some of the victims have filed a motion to ask that the case be temporarily suspended until a new president comes to power, saying they have completely lost all trust and confidence in the present justice system," she said.
"The fear since Ampatuan Jr's press conference is that at some stage the administration or those close to the clan might perform some sort of sleight of hand, allowing the primary suspects to walk away either scot-free or with a commuted sentence, should they even be charged."
Our correspondent added that the trial judge arrived in court on Wednesday under heavy security escort after reportedly receiving several death threats.
Several other potential witnesses have reported threats or intimidation.
During Tuesday's press conference, Ampatuan Jr thanked Alberto Agra, the Philippines justice secretary, for deciding to drop murder charges against two members of the Ampatuan clan on April 17.
|Andal Ampatuan Sr, centre, and his family had been close allies of President Arroyo [Reuters]
He also denied suggestions that his family had bribed prosecutors to drop the murder charges against the two.
"We had no arrangements with the justice secretary or Arroyo," he added.
The decision not to prosecute the pair sparked street protests and public criticism from government prosecutors.
Monette Salaysay, the 55-year-old wife of the slain editor of a provincial tabloid, said Ampatuan Jr was trying to fool the public.
"How can he pretend to be innocent?" Salaysay asked. "If you can open my heart you won't find anything but pure hatred against these killers."
The November 23 massacre was unprecedented in a country known for election violence and political killings that have claimed hundreds of lives in the past decade.
Witnesses have testified in court that Ampatuan Jr led dozens of gunmen in holding up a convoy of the rival Mangudadatu clan members, followers and journalists as they were about to register their candidate to run in local elections.
They were later shot on a nearby hilltop.
Three days after the killings, Ampatuan turned himself in to police.
Prosecutors later filed an indictment against his father, clan patriarch Andal Ampatuan Sr, and dozens of others accused of involvement in the massacre.