The casket was adorned with children's drawings. A toy of Simba the cub, from the popular kids' animated movie The Lion King, sat amidst a floral wreath.
Marley's devastated mother Natalie and his older sister Briana Brockless-Lodge spoke lovingly of a little boy who "lit up our lives".
Natalie rounded off an emotional eulogy with the Serenity Prayer.
Briana recalled a mischievous youngster who was full of fun.
"Marley loved animals and he will always be loved and missed," she said.
The pews were decorated with green bows, while the floor at the front of the church was laid out like a mini-jungle scene, with cut-outs of wild animals and paper trees.
During the service, Marley's dad Bill comforted his tearful wife as Father Craig Dunford spoke of the tragedy.
"Marley was taken from us far, far too early," Father Dunford said. "But Marley is okay. It is us who are not okay, as we try to make sense of what happened."
Following the service, mourners let dozens of green balloons drift off into clear blue Auckland skies.
A serious crash unit investigation is under way into how the driveway tragedy occurred. Police said the driver of the roller was related to Marley.
Police say any decision on charges is two to three months away.