Prisoner disfigured by stabs to face

File photo of a riot at Spring Hill prison in June 2013. Photo / Doug Sherring

A 29-year-old inmate suffered "disfiguring" injuries with a sharp weapon after a stabbing at Spring Hill Prison last night.

Waikato Detective Senior Sergeant Whitehead said Corrections staff were alerted about 8pm yesterday.

The prisoner was initially rushed to Waikato Hospital in critical condition, but was stabilised overnight.

"The inmate was treated for several injuries that appear to have been inflicted with a sharp weapon. A number of these are to his face.

"Although disfiguring, these injuries are not life-threatening," Mr Whitehead said.

At the time of the assault the victim was among a group of prisoners who had free access to their cells and a common exercise area.

The victim remained in hospital under guard but was expected to be returned to prison tomorrow, Mr Whitehead said.

"A team of police investigators are currently at Springhill Corrections Facility. They are being assisted by Corrections staff and police and ESR forensic specialists."

It's still unclear what led to the incident.