The criminal case against Naveed Akram, accused of playing a role in the Bondi terror attack, faces further delay after what prosecutors described as an "unprecedented" investigation by the joint counter-terrorism team.

The matter was adjourned on Wednesday at Sydney's Downing Centre local court and will not return until 24 February. Prosecutors expect to be ready by then to certify the charges against Akram, who has yet to enter a plea.

Akram, 24, and his 50-year-old father, Sajid Akram, allegedly murdered 15 people after opening fire at a Hanukah festival at Bondi beach on 14 December. Forty people were injured. Naveed Akram survived a shootout with police, while Sajid Akram was shot and killed at the scene.

Naveed Akram has been charged with 78 offences, including 15 counts of murder and one count of committing a terrorist act that investigators allege may have been "inspired by Isis". He was initially charged with 59 offences in December, and 19 more were added in April as the investigation progressed.

Prosecutor Danielle New applied for the adjournment, and Akram's defence team did not oppose it. She told the court that prosecutors had now completed their brief of evidence, a process that had also been slowed by the sheer volume of material involved. Judge Karen Stafford granted the request.

New argued that more time was needed so investigators could consult the alleged victims and their next of kin about the charges before the offences are certified. Certification is a standard step in a criminal case, in which prosecutors formally list the offences proceeding to trial.

She said her team did not want to "rush" the consultations and was conscious that Hanukah was approaching, along with the Christmas holidays and the summer shutdown period for the courts. "It's important the crown goes over everything again, to make sure no person's narrative is left untold," New said.

According to New, the brief of evidence includes thousands of witness statements, medical records, financial statements and records of purchases made by the Akrams, as well as footage from Bondi beach on the evening of the attack. "The [joint counter-terrorism team] has engaged in an investigation the size of which has been unprecedented," she told the court. "The commitment by all involved is nothing short of highly professional."

In December, a police fact sheet released via the courts outlined the allegations against Naveed Akram at that time. It alleged there was evidence that the pair "meticulously planned this terrorist attack for many months", including the creation of an "ISIS inspired" video, firearm training and the making of explosives.

The document also alleged that the pair made a "reconnaissance" visit to Bondi two days before the attack. They allegedly visited the footbridge from which they are accused of deliberately firing at people gathered at the Jewish festival.