Naveed Akram was charged with 19 further offences in Sydney's Downing Centre Local Court on Wednesday, adding to his 15 existing murder charges and other allegations.
Numerous devices and thousands of images connected to the Bondi Beach shooter are being examined as part of the evidence underpinning the fresh charges.
"In a matter of this magnitude, it's not unusual for additional charges to be laid," Akram's lawyer Leonie Gittani said outside court.
"It's an unprecedented matter so ... we've got a job to do."
The 24-year-old is accused of opening fire on a crowd of people celebrating Hanukkah at Bondi Beach alongside his father, 50-year-old Sajid Akram, on December 14.
The attack left 15 people dead - including a 10-year-old girl - and dozens more injured.
The elder Akram was shot dead by police, while his son was taken into custody.
He was charged with 59 offences and is being held at Goulburn's supermax prison.
The existing charges included committing a terrorist act, 15 counts of murder and 40 charges of attempted murder over his role in the massacre.Â
Prosecutor Danielle New confirmed 19 additional charges, including 10 counts of shooting with intent to murder and six counts of discharging a firearm with intent to resist arrest, were added to Akram's charge sheet on Wednesday.
Akram's case was adjourned for nine weeks because of the sheer weight of evidence being assessed by investigators.
"The Joint Counter-Terrorism Team are progressing really steadily and well through the preparation of this matter," Ms New said.
"The outstanding evidence ... includes 230,000 images from CCTV.
"There are numerous devices from other persons purportedly linked to the defendant ... they require translations."
The lengthy adjournment, two months beyond the usual six-month limit for cases in the local court, was approved by Deputy Chief Judge Michael Antrum.
"I'm sure there is a significant volume of material ... the brief needs to be in good form," Judge Antrum said.
Outside court, Ms Gittani foreshadowed there would be no quick resolution to the legal proceedings.
"There's still a lot more brief to be served, so until that time comes we're not in a position to enter any pleas," she said.
"The matter is still in its infancy ... from a legal perspective."
Before the charges return to court, a hearing on June 29 will assess the extent of suppression orders protecting the identity of certain victims and police officers caught up in the atrocity.
Ms New gave the court evidence of the significant psychological harm experienced by people whose identities were made public in similar cases.
Police officers who were present on the day or involved in the investigation are more likely to feel confident giving evidence if their names are protected, the prosecutor said.
Akram has not yet been required to enter pleas to any of the charges against him and was not required to appear by audiovisual link.
The father-and-son attack was Australia's deadliest mass shooting since the Port Arthur massacre in 1996.
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