Clutching single gerberas, the families and friends of victims and survivors gathered on the Dolphin Point headland at Coogee Beach, near the memorial to the 20 eastern suburbs victims.
It’s the first time that the annual Coogee service has been addressed by the siblings and children of victims of blasts.
Ben Borgia, 27, who lost his mother and teenage sister in the attacks delivered a heartfelt tribute to them, which moved many in the 300 strong crowd to tears.
He said he is still struggling to accept his loved ones won't be coming home.
"For the last four years I've had to learn to cope with the reality that the people I love most in the world aren't coming home from Bali," Mr Borgia said.
"How can this happen to the people that we love? I could not and cannot to this day fathom what happened."
Mr Borgia's sister Abbey was 13 when she died. His mother Debbie was 45.
"I'd just like you to think for a second of all the things you have done since you were 13 years old - your first kiss, love, marriage, books, travel, choices, independence. There's so much fun to be had," he said.
"Abbey, my sister, would be 17 today. It is difficult and wonderful to see her friends grow up."
Acting New South Wales Premier John Watkins backed South Australian Premier Mike Rann's calls for October 12 to be made a national day of remembrance for Australian victims of terrorism.