Molly Owens was reported missing from Holyhead, in Anglesey, on Friday.
Police have said they believe she is with her father, 26-year-old Brian Owens.
He had been due for sentencing at a court in Caernarfon on Friday but did not attend the hearing. Officers have not given details of his original offence but said a warrant had been issued for his arrest.
Molly is described as having collar-length blonde hair and blue eyes, while Owens is 5ft 9in and slim, with short brown hair and blue eyes.
Chief Inspector Sharon McCairn said police were "concerned for Molly's whereabouts" and appealed for anyone with information to contact police.
"Equally I am issuing a direct appeal for Brian Owens to make contact with us to let us know that both he and Molly are safe and well," she said.
Anyone with information is asked to contact North Wales Police by calling 101.
source: skynews