The operator of Mt Eden prison has been fined $150,000 after a prisoner escaped.

The company, Serco, and the Corrections Department have carried out a review of security after notorious inmate Aaron Forden escaped from the prison in the early hours of October 10 last year.

The two groups say both operational security and the physical security of the building infrastructure have now been enhanced.

Department of Corrections chief executive Ray Smith says a portion of the payment to Serco for the management of Mount Eden prison is performance-related.

He's says it's appropriate to levy a financial penalty for the escape.

Serco managing director Paul Mahoney is confident in the improvements to both the operational and physical security of the building.

"From time to time these sorts of issues do happen in the prisons. But we believe the processes in the prisons are very strong and that the likelihood of similar occurrences are very low."

The $150,000 fine has been levied because the escape breached Serco's contract with the Corrections Department.

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