A look inside life at Cessnock prison half a century after it opened

But the days of locking prisoners up and throwing away the key are long over, and the centre has a strong focus on education, support and making sure inmates find a sense of purpose.

Cessnock Correctional Centre governor Mick Dudley has worked at the facility for 16 years and said it had been through a number of phases since it opened on June 26, 1974.

"It's quite remarkable to see what's happened at this complex," he said.

"Probably the main thing is the way that we're interacting with the community now."

The original centre opened with a capacity of about 450 and has since expanded to house about 1500 inmates across three separate centres at the complex.

He said many worked at private businesses outside the centre, were studying trades, engaging in support programs and working on projects inside the centre like building movable homes for communities in need or manufacturing textiles like sheets and gowns for hospitals.

"It makes a difference to the community," Governor Dudley said.

"We know that it's really starting to make a difference to re-offending, and it really is significant.

"We're trying to give them a whole new focus and we believe we're doing that ... we all need a purpose in life."

Inmates are also engaging in cultural programs in an effort to ensure fewer Aboriginal people are returning to custody.

"Everybody knows across the state that Indigenous incarceration rates are way too high," Governor Dudley said.

"It's not just professional things ... it's an opportunity for inmates to do things that are innovative and change their future and their family's future."

The Herald was invited inside Cessnock Correctional Cenrre for a rare tour on the 50th anniversary on Wednesday.

For more than 200 inmates there each day, their morning starts when they're woken up just after 6am.

They get their breakfast and head off for a full day of work. They may also do part of their study or traineeship during that time.

At the end of the work day, they go back to the accommodation areas and access their programs or other facilities like ovals.

There are newer buildings and older buildings for protection prisoners and general population, mostly with one person per cell, and each has an iPad.

In 34 years working with Corrective Services NSW in different roles, and more than 20 years at Cessnock Correctional Centre, David Harrower ACM has seen "enormous" changes for inmates.

He said the introduction of assessing the criminological needs of inmates - such as drug abuse or domestic violence - had helped target programs to them.

"We're proactive and ... we're supporting people that will one day go back into the community, and we want them to do that as a better person, more educated and with skills that will help them cope," he said.

In his decades on the job, he had been affected by deeply troubling instances of self-harm and lost co-workers to suicide.

He said mental wellbeing had become a bigger focus, with more support available, and the camaraderie between officers was important too.

"Once if an incident took place, it was just asked 'are you okay' and, men, they say 'yeah I'm fine', but we weren't fine ... it's improved greatly," he said.

"We're a family in blue ... we have to help each other, because if we don't, we're all in trouble."

Before he was at Cessnock Correctional Centre, Mr Harrower spent time at Maitland Gaol, where notorious backpacker serial killer Ivan Milat worked as his "sweeper", helping keep the office tidy.

"I've never treated any inmate any differently. It's not my place or a custodial officer's place to judge, the courts have done that, our role is the custody care and control," he said.

"You do get satisfaction at times because you know you're making a positive contribution to someone's life and you're helping them."

Cessnock Corrrectional Centre was opened 50 years ago by Governer General Sir John Kerr. A flag-raising, traditional smoking ceremony and formal celebration was held at the facility on Wednesday, and staff dating back to the first days in the 1970s attended.