The final heartbreaking and horrific moments of the youngest Christchurch Mosque massacre victim has been detailed by his grieving family.

Mucaad Ibrahim, three, was inside the Al Noor mosque in Christchurch on March 15 with his father Aden, 60, when accused Australian terrorist Brenton Tarrant allegedly stormed the building and killed worshipers.

According to the young boy's devastated family, Mucaad was sitting on his father's lap and had just kissed him on the cheek when they heard gunshots.

Within seconds, Tarrant allegedly shot Mucaad in the chest and continued to fire until Aden fell to the ground with his son in his arms, The Advertiser reported.

As the blood of his son and others that had fallen on top of him pooled, the 60-year-old believed Mucaad was dead.

Then suddenly Mucaad moved and uttered his last words: 'daddy, daddy'.

But the gunman heard the three-year-old cal out to his father and allegedly returned to shoot Mucaad in the head, the publication reported.

The final heartbreaking and horrific moments of the youngest Christchurch Mosque massacre victims, Mucaad Ibrahim, has been detailed by his grieving family (pictured)

Mucaad's sister Luul Ibrahim, 31, recalled her brother's horrific final moments.

'The sad part of it is that after the first shot he was still alive, why did he shoot him a second time? He took that as a joke. The joke is on him. Nobody knows who he is. Mucaad has left a legacy of love,' she told the publication.

The shock of the horror unfolding around him caused Aden to pass out. He later regained consciousness and cradled his son until the shooting stopped.

Aden then walked from the Mosque with his son's body in his arms.

'Dad will never forget how Mucaad kissed him, the last kiss he had ... we’re in a state of shock. Maybe later we’ll start to grieve,' Ms Ibrahim said.

The 'energetic and playful' boy was among the final group of victims to be buried on Friday. Fifty people lost their lives during the attack. Another 50 were injured.

Mourners carry the casket of the youngest victim 3-year-old Mucaad Ibrahim at the Memorial Park Cemetery in Christchurch on Friday

Family members wearing dark robes carried his tiny body in a coffin as he was laid to rest as part of the mass funeral at Christchurch's Memorial Park.

The small Somali-born boy with big brown eyes barely filled half his coffin.

More than 5000 mourners gathered at the cemetery for the funeral, which began at 4pm NZT (2pm AEDT).

Friday's funeral crowds stretched from a marquee reserved for prayers all the way to the freshly dug graves across the lawn cemetery.

Australian man Brenton Harrison Tarrant, 28, has been charged with one count of murder over the massacre that saw 50 people killed.