Guests gathered at the Manukau Memorial Gardens in South Auckland today.
Black and white balloons with the number 11 - paying tribute to Lomu's jersey number - have been tied down nearby. Other balloons have the words: "Love You Dad."
Lomu's wife, Nadene Lomu, attended with the couple's two sons, Brayley (10) and Dhyreille (9).
Brayley Lomu brought tears among guests as he struggled to give a prepared speech.
He thanked everyone for coming, before crying into his mother's arms.
She acknowledged the event was very short notice, but was happy to have representatives from all sides of the extended family.
The rugby great's brother John and an aunt who has travelled from Australia were among members of the Lomu family attending.
Guests include former All Blacks Eric Rush and Josh Kronfeld and Lomu's former manager Phil Kingsley-Jones.
A musical tribute featured Chicago's You're the Inspiration.
A prayer was said before John Lomu gave a brief speech.
He paused, seemingly gathering himself, before saying: "It's time to be together as a family.
"Thank you everyone for being here."
Family friend Sela Alo paid tribute to a young man with a generous spirit.
"It's a beautiful occasion. We should... celebrate it. No matter what walk of life you come from, we should celebrate that."
Referring to the clouds above, Aho got laughs from the crowd when he said: "Jo-jo, you could've at least put some sun out bro!"
Sevens legend Rush also shared a few jokes, saying of his old mate: "He had an impact on a lot of people. Josh Kronfeld is here - he had a lot of impacts."
Rush said many of them often forgot just how great a rugby player Lomu was, acknowledging many of the impossible tries he used to score.
"You don't see those tries today."
Rush also acknowledged two other rugby greats now lying at rest nearby - former Manu Samoa great Peter Fatialofa and former All Black Dylan Mika, who died in March aged 45.
The Herald on Sunday revealed yesterday that a fresh row had broken out between Nadene Lomu and the rugby great's family over the headstone unveiling.
Lomu's side of the family were only told about it on Thursday and they were concerned that they did not know what the headstone would say.
Lomu's mum Hepi missed the ceremony as she flew to Fiji on Friday on a trip arranged before she knew of the plans.
The All Black great died on November 18, 2015 of a heart attack following a long battle with kidney failure.
Nadene Lomu is in charge of his grave at the Manukau Memorial Gardens.
