The ISIS-loving father-son duo accused of carrying out the antisemitic Bondi Beach massacre had amassed an arsenal of homemade pipe and “tennis ball bombs” and railed against “Zionists” in the lead up to the terror attack, newly released court documents reveal.

The detailed preparations and alleged motives of Sajid Akram, 50, and his 24-year-old son Naveed Akram were laid bare in court papers made public on Monday after the pair were accused of slaughtering 15 and injuring dozens more at a Hanukkah celebration on Dec. 14.

On the day of the mass shooting, the pair were caught on surveillance video carrying long and bulky items that were wrapped in blankets from an AirBnb they rented in Campsie – a neighborhood in Sydney’s southwest – that served as their planning base, cops allege.

Police believe the items wrapped up were the cache of weapons they allegedly stockpiled for the attack — including two shotguns, a Beretta rifle, three pipe bombs, a tennis ball bomb and a large improvised explosive device.

The tennis ball bomb contained an explosive, gun power and steel ball bearings, cops allege.  

The hate-filled duo are accused of hurling the pipe and tennis ball bombs at the crowd of Jewish worshippers who had gathered at the famed beach to celebrate Hanukkah — but the devices failed to detonate, the court documents state.

Moments after hurling the IEDs, the Akrams then allegedly opened fire from a nearby footbridge, which provided them an elevated vantage point and the protection of waist-high concrete walls, according to the police files.

Police allege they uncovered 3D printed parts for a shotgun component, as well as bomb making equipment and copies of the Quran, at the rented home in the wake of the attack.

Investigators later recovered a cellphone video recorded in October where the two men allegedly justified the meticulously planned attack as they were flanked by rifles and an Islamic State flag, authorities allege.

“The accused is recorded appearing to recite, in Arabic, a passage from the Quran,” the filing states.

“Following the recitation, both … speak in English and make a number of statements regarding their motivation for the ‘Bondi attack’ and condemning the actions of ‘Zionists.’”

Separate footage recorded that same month captured the father and son allegedly training for the attack by “firing shotguns and moving in a tactical manner” in a remote area.

The footage, as well as the cache of weapons uncovered in the aftermath, proved the Akrams had “meticulously planned this terrorist attack for many months,” the court papers state.

The details were unsealed after Naveed Akram’s video court appearance from a Sydney hospital where he has been under police guard since being injured in the shooting.

Naveed, who was transferred from the hospital to a prison on Monday, is charged with 59 offenses, including 15 counts of murder, 40 counts of causing harm with intent to murder in relation to the wounded survivors and one count of committing a terrorist act.

His father, who legally owned six rifles and shotguns, died at the scene after being taken out by cops.

With Post wires