Police are yet to find a man with an extensive criminal history who escaped from a Waikato prison early today.

Paul Kyle Peekay Rehua escaped from a medium security unit at Waikeria prison, south of Te Awamutu, between midnight and 6am.

Police looked for Rehua at known addresses in the Waikato area but were unable to locate him, Senior Sergeant Dave Simes, said.

He is described as Maori, 176cm tall and of thin to medium build. He has short dark hair and a moustache.

Corrections regional manager Jeanette Burns said it was extremely concerned about the breach of security and it was doing everything it could to help police find the man.

Full details of how the prisoner escaped were not yet known, and may not be known until the prisoner had been recaptured and a review of the escape completed, Ms Burns said.

"We will be looking closely to see what exactly occurred so that we are able to put in place measures to stop it occurring again."

Police said Rehua had links to the Waikato and Te Awamutu areas.

They said anyone with information should report Rehua's whereabouts to them but should not approach him.