"Tahu is now with his whanau at Otamatea Marae and will be there for the duration of his tangi. At this stage the whanau have advised us that the funeral service for Tahu will take place on Monday. Feel free to contact us for further information, whanau."
One relative, who did not wish to be named, said the devastating news was still sinking in.
"We're all just in such shock. He was the baby of the family," the woman said.
The driver of the milk tanker worked for Fonterra. Its managing director of global operations, Robert Spurway, said the company was working with police and supporting the driver and local community.
"This is a terribly tragic accident and our thoughts are with the child's family and loved ones."
A resident of Gorge Rd, where the fatality occurred, said Tahu's family were well known and respected in the community and had lived there for at least 11 years.
She said the incident was "devastating".
"Something like this, with a death, impacts hugely. It is going to affect everyone," she said.
"When I found out what happened, my heart sank. I know the family, my heart breaks for them."
Police said Tahu was riding his bike on the footpath on Gorge Rd with his 7-year-old brother and a 5-year-old girl.
"He has fallen off his bike into the road and unfortunately been run over by the wheels of the trailer and he's passed away at the scene," said Inspector Wayne Ewers, acting road policing manager for Northland.
"It's absolutely devastating, as you can imagine, for the family [and] emergency services involved and it's just an unfortunate day."
Mr Ewers called the death a "complete accident". Speed was not a factor.
It's the fourth fatal road incident in Northland this year. On Monday, 82-year-old Aucklander Bruce Murray Stenning was killed in a quad bike crash in Kellys Bay, near Dargaville, which also injured his 62-year-old partner.
Last Saturday, a 63-year-old driver died when his vehicle rolled on State Highway 1 near Waipu, and on January 12, a 45-year-old driver died when he crossed into the path of a southbound, fully laden logging truck on Smeatons Hill near Oakleigh.