Inmates at a Christchurch prison have concocted a toxic home brew out of hand sanitizer, getting drunk off the novel drink.

APNZ reports hand sanitizer was given out to Christchurch residents to help prevent the spread of disease after the deadly February earthquake, and Rolleston Prison bosses decided to do the same.

But three enterprising inmates have used the germ killer as the base for a brew, adding sugar-based products like powdered fruit drink to sweeten it.

Inmate Tuarea Pahi, 24, got drunk and assaulted a prison officer, an attack he says he doesn’t remember.

It came as a shock to the officer because they had reportedly been on friendly terms before then.

An extra 70 days has been added to Pahi’s jail term after admitting the assault at a district court session inside the prison.

The court heard how Pahi and two other inmates were caught "highly intoxicated" on September 4.