The two-year-old girl was out for a bike ride with her mother and brother on Tuesday morning in Harkness.

She fell behind and when her mother turned around she saw a man had grabbed her daughter by the wrist and was pulling her bike in the other direction, police say.

The 32-year-old woman rode towards her daughter, and the man let go and ran away.

The girl suffered redness to her wrist and was "shaken up", police said, but was otherwise unhurt.

Detectives are still hunting the man on Wednesday and said they were following up a number of leads.

The mother has spoken to the media and she believes it was an attempted kidnapping, but police aren't willing to speculate on the man's motive yet.

"Until we know exactly why something's happened, we are concerned about the behaviour," Detective Acting Senior Sergeant David Leveridge told reporters on Wednesday.

"Until we speak to the person concerned, we've got to treat it extremely seriously."

Det Leveridge said police believed it was a "one-off incident" but are taking extra precautions.

"I want to reassure the public we're dedicating more resources to that area," he said.

Police say the offender is of African appearance and in his early 20s, was not wearing a mask and dressed in dark clothing with a white baseball cap at the time of the incident.

Anyone with relevant information is urged to contact police or Crime Stoppers.

Australian Associated Press