He is described as Maori, of medium-build with short, dark hair and a height of about 175cm.
Anyone with information about his whereabouts is asked to immediately call 111.
Cowan is the latest runaway in a string of incidents reported by police.
South Auckland man Thomas Shortcliffe sparked a police manhunt when he cut off his electronic monitoring bracelet less than a week ago.
Shortcliffe assaulted a security guard after he cut off his bracelet about 11pm on August 29.
He escape came just a day after Zane McVeigh, 19, allegedly breached his parole conditions by removing his monitoring bracelet and fleeting his Wellington property.
In August, Southland police were hunting Michael George Mulligan, 30, who was on electronically monitored bail and facing driving and domestic violence charges.
Convicted child sex offender David Livingstone was also being hunted down after allegedly removing his electronic monitoring bracelet to escape his Wellington abode. He was arrested by police two days later in the Hutt Valley.
Last year Tony Robertson murdered and raped North Shore woman Blessie Gotingco while on monitored release for child sex offending.
There are more than 3200 offenders on the electronic monitoring system introduced in February, of which 1832 are also monitored via a real-time GPS system.
