"There have been hard times," departing Corrections boss Barry Matthews says with his trademark stern look and without a hint of knowing that he is stating the obvious.

Indeed, there were some mornings when he woke up and questioned what he was doing heading a "landmine" of a department.

For nearly six years, Mr Matthews has presided over a department that has been in the news for all the wrong reasons. The department-related deaths of Karl Kuchenbecker (gunned down by parolee Graeme Burton) and Liam Ashley (strangled by George Baker when they should not have been in a prison van together) rate as some of his darkest days.

He was even briefly known as Barry "no blood on my hands" Matthews after a poor performance at a press conference following Mr Kuchenbecker's murder.

Then his job was under a cloud when incoming Corrections Minister Judith Collins refused to express confidence in him.

And let's not forget the prisoners, quickly filling up all jail beds and claiming life was easy on the inside. Some watched pornography on their cellphones. Some bribed guards for drugs and other luxuries.

"You are under pressure at different times, and it's actually much harder on the family because they read all the papers and all the scathing comments," Mr Matthews told the Herald.

"There's been various times where my family have said, 'Dad, why did you take it on?' You knew you were walking into a bit of a minefield', and a procession of ministers had come and gone. I had no illusions about that. But I'm a person who likes challenges. If everything was running smoothly, I would probably get bored."

A former police deputy commissioner, Mr Matthews, 64, is retiring on Friday after 45 years' public service. He will be replaced by Ray Smith, deputy chief executive of Child, Youth and Family.

So on Christmas Day, Mr Matth-ews, a father of three and grandfather to six, will wake up as a man of leisure.

"I suspect I'll wake up and think, 'Gosh, no one's rung me up to sign a contract or sought my advice on something'."

His immediate plans: "Holiday, break, a bit of travel, a bit of sailing.

"There was a story about HMS Corrections, that mythical boat that corrections inmates had worked on. I know there was a rumour going around that it was my boat."

It wasn't, he insists, and in fact he never found the boat at the centre of the claims.

Mr Matthews says getting cellphones jammed in every prison is one of his career highlights.

"We had one prisoner who had escaped and rung up to order a taxi so that when he got over the wall, he could get away. We were getting contraband thrown over the wall where the prisoner was able to ring the person outside and say, 'Right, throw it over now'.

"And we had the claims by one of the women in Arohata saying she was able to smoke P, and watch porn on her cellphone."

Yesterday, the Herald highlighted a story where a prisoner was updating his Facebook page from a phone, and Mr Matthews admits the jamming technology needs to be constantly updated to keep pace with new services.

He insists the department has turned a corner and is performing well. Although recidivism rates are stagnant, escapes and positive random drug tests are down, numeracy and literacy programmes and drug treatment capacity are up, and the muster crisis is over (for now).

"I don't have any great regrets. I feel pleased where things are at the moment and it's in a good state for my successor. And there's still more to do," Mr Matthews said.

"But I won't miss picking up the paper and seeing speculation as to whether I'm going to get sacked. I won't miss that at all."