Powell, aged 30, is wanted for recall to prison after breaching the terms of his release licence.
Officers have been making enquiries in and around the York area in an effort to locate Powell, who was released from custody last month after being jailed for robbery.
Powell is believed to have links in the Northampton area.
Officers are appealing to the public to remain vigilant and report any sightings of Powell or anyone matching his description to the police or Crimestoppers.
Powell is described as white, around 6ft tall, with a medium build and dark brown hair.
Anyone who can help to locate Michael Powell should contact North Yorkshire Police on 101 – select option 1 – and pass information to the Force Control Room.
If you prefer not to give your name, Crimestoppers can be contacted anonymously on 0800 555111.
Please quote reference number 12140112879 when passing information about this incident.