Rockdale father-of-five John Mewburn among 12 prison officers honoured on annual remembrance day

John Colin Mewburn, 46, who was married with five daughters aged 17 to 26, was hit with a hammer while his back was turned by Peter Schneidas, one of the state's most challenging inmates.

He is among 12 prison officers who died in the line of duty over the past 179 years.

Minister for Corrections Geoff Lee said November 25 was an important opportunity for the community to reflect upon the challenging and often dangerous work corrections staff perform each day.

"The work of corrections staff doesn't often happen in the public's view, but they're out on the frontline every day, whether they're managing inmates in prisons or attending offenders' homes for parole supervision," Dr Lee said.

"They're brave men and women, who go about their work with a dedication to duty and professionalism despite the dangers they face each day.

"Today my thoughts are with all corrections officers as we commemorate those who've made the ultimate sacrifice to keep their family in blue and the NSW community safe - you will never be forgotten."

Commissioner Kevin Corcoran said prisons would go into lockdown and flags will be flown at half-mast as families and friends gather at memorial ceremonies around the state.

"When our officers clock on each day, we expect to return these men and women home safely to their loved ones at the end of their shift," Mr Corcoran said.

"Tragically, there have been instances in our history when officers didn't come home. We acknowledge the devastating loss suffered by the families, friends and colleagues of these men."

Mr Mewburn had been a farm worker before moving to Sydney to provide more opportunities for his children.

He was well liked by inmates, who collected for a wreath after checking his widow would not be offended.

Mr Mewburn's elder brother Ernie said, when they attended the trots together, ex-prisoners would often come up and thank John for the kindness.