An employee of Otaika Dairy, Rakesh Kumar, said the boy and a girl about the same age approached the pedestrian crossing from the south end and stopped for traffic before crossing.
The boy was hit by a southbound car and was thrown about 12m, according to Northland police road policing manager Wayne Ewers.
The girl and people outside the shops rushed to help the injured boy before emergency services arrived.
The female driver of the car that allegedly hit the boy stopped about 20m from the crossing and got out.
Police could not confirm whether the driver was local but she was spoken to while the boy was helped by St John paramedics before being taken to Whangarei Hospital with serious head injuries.
Serious crash investigator Senior Constable Warren Bunn and Mr Ewers were at the scene gathering information on the circumstances leading to the accident.
In 2010, the NZ Transport Agency carried out major improvements to the pedestrian crossing after local resident Pauline Edwards started a petition following numerous crashes there.
Then-Prime Minister John Key also signed the petition on a visit to Whangarei in October 2010.
The upgrade included improved lighting, using a red, textured surface on the pedestrian island to make it more visible, laying a skid-resistant surface on the highway approaches to the crossing to improve braking and placing the traditional black-and-white pedestrian crossing on a red surface.
Line-marking around the crossing was improved as well.
Retired safety engineer Dave Murray was one of several who had petitioned for various changes to the crossing and was successful in having a "safety" fence removed early this year which hid pedestrians waiting to cross from ongoing traffic and vice-versa.
Mr Kimber, who has run his shop on and off for 25 years, said the situation was a little better after improvements were made but he believed the pedestrian crossing would continue to be a risk to road users.
"Either lights or an overhead foot bridge, accidents will continue to happen. With lights, people and especially kids will play on it and unnecessarily slow down traffic.
"An overbridge will cost massive amounts of money but then any vehicle too big won't fit under it so this will continue to be a very dangerous intersection," Mr Kimber said.
He said about 20 years ago, a pedestrian hit by a vehicle was flung almost to the doorway of Four Square.
"It's damn sad ... coming into Christmas. It's going to ruin someone's Christmas," he said of yesterday's accident.