Russell's email described the "suspicious" man as having long dark hair, a tattoo on his left arm and driving a white van, possibly with tinted windows.
"The student involved is safe and did all the right things, reporting the incident as soon as they arrived to school," she said.
She urged parents to discuss the incident with their children "so they know what to do if they are approached or confronted".
"It is a very pertinent reminder that student safety in our community is paramount."
Cunningham said police will conduct additional patrols in the area and will be highly visible before and after school this week to reassure the community.
"We acknowledge that any incident of this type is concerning to parents but we can reassure the community that we are taking this matter very seriously."
He said police were working closely with the school, and urged anyone with information to contact police.
A similar incident was reported last month, but police found nothing suspicious after speaking to the driver.
And on February 28, a man tried to grab an 11-year-old girl on her way to St Heliers School, in East Auckland.