The inmate who committed the assault is a Mongrel Mob member, the Herald understands. Photo / Hawkes Bay Today / Sarah Bicknell

A Mongrel Mob inmate stabbed an officer 12 times in the face in a harrowing assault at Hawke's Bay prison on Wednesday evening.

It is the second vicious shanking attack in Kiwi prisons this month and comes amid rising violence in the Corrections system, coupled with a serious staff shortage.

The attack at Hawke's Bay Regional Prison on Wednesday involved an inmate with a reputation for violence, who is a member of the Mongrel Mob.

He stabbed the officer 12 times in the face with an improvised metallic weapon.

The inmate has previously attacked officers.

Corrections Association President Floyd du Plessis said the officer was at home and expected to make a full recovery.

Du Plessis said the attack was appalling.

The effects of the assault were being felt throughout Hawke's Bay prison, suffering from the same staff shortages plaguing the entire prison network. It is currently running on contingency plans due to low officer numbers.

"It's a cowardly, shocking attack on a staff member," Du Plessis said.

"It was a savage assault. The effects are so widespread.

"It's a shocking statement to make."

Hawkes Bay Regional Prison acting director Leonie Aben said police were investigating the assault and the prisoner had also been charged with misconduct via Corrections' internal disciplinary system.

"The prisoner is known to staff and was on directed segregation. He was scheduled to be transferred to another prison site today," she said.

"While he was unlocked for recreation yesterday [Wednesday], staff were taking him a trolley to collect his property and he suddenly assaulted one staff member with an improvised weapon.

"Other staff immediately intervened and restrained the prisoner."

The officer was taken to hospital and discharged last night, she said.

"They are being offered ongoing support and will remain at home until they are ready to return to work."

The inmate was moved to another prison today as planned.

On Friday, June 10, an associate of the notorious international biker gang the Mongols attacked a Corrections officer with a sharpened toothbrush at Spring Hill prison in Waikato.

Corrections officers at Spring Hill prison in Te Kauwhata were preparing to unlock the man for recreation time when he attacked one staff member while still handcuffed, prison director Scott Walker said.

He then stabbed the staffer with a sharpened plastic toothbrush handle, a commonly used improvised weapon in prisons.

There were 909 assaults of varying severity committed against Corrections staff in the year to May, a percentage increase of 156 per cent from the 355 assaults in 2013.

That resulted in more than 6200 workdays being lost over that period as staff recovered from their injuries.

The frequency of assaults has risen even while the prison population has regularly declined since 2018 - dropping to 7927 from 10,540 four years ago.