Acting principal Greg Lees said they would discuss whether pupils would be told about Friday's incident, as he did not want "a whole lot of alarmed or frightened children''.
"As far as we're concerned there was no incident but there could have been,'' he said.
"We've had the assurance from the police that there is going to be a bit of a presence.''
He was not prepared to go into details of the incident for the well-being of the child affected and other Fairfield School pupils.
Mr Lees sent an email to parents on Friday alerting them about the matter.
The email was then posted on Facebook by members of the public.
"An incident occurred today ... when a man with light brown hair in a blue car was seen several times driving in the area of Main Road, Martin Road and Fairplay Street,'' Mr Lees said in the letter.
"He pulled over and asked directions from a Fairfield child before making a comment of a sexual nature. Thankfully, this child was able to avoid the situation by following stranger danger rules.''
The letter went on to say parents should remain vigilant and although it was the school's responsibility to inform the community, the school did not "see the need to alarm your children''.
Police would not comment yesterday about what police "presence'' meant or where the investigation was at.
Police issued a statement on Saturday asking for help from the public to identify the man "who made inappropriate comments'' to a pupil.
Police described him as a clean-shaven Caucasian with dark hair, shaved at the sides, aged 20 to 30.
The car he was driving was a light blue four-door hatchback with black seats or seat covers and it appeared the windows were wind-up, not electric, the statement said.
"Police will have a presence around the school in the coming days and request any other students who are approached by anyone suspicious to tell a parent or teacher as soon as possible.''
Police encouraged parents to reiterate safety to children and to walk to school in groups where possible.
In March, two schoolgirls were left upset and scared after being approached by strangers in South Dunedin.
