Grandfather fears white supremacists grandson's release will end in tragedy unless support put in place

Rod Finch's grandson is due to be released on Friday. Photo / File

A grandfather is pleading for authorities to step in and help his white supremacist grandson who has promised he will kill someone.

Rod Finch has serious concerns over the mental wellbeing of his 22-year-old grandson, Frank, who is due to be released from prison on Friday.

Speaking to 1 News, Finch said after the Christchurch mosque shootings his grandson applauded the alleged gunman and promised to kill if he got out.

"What did I think at the time? Thank god he's behind bars. I knew he was safe, and the public are safe," he told 1 News.

"It's a matter of time and Frank will kill. I have no doubt about that."

Frank is currently in Christchurch Prison and was registered as schizophrenic two years ago and is also addicted to drugs and alcohol.

The grandson applauded the actions of the alleged mosque gunman.

He was sent to prison in December last year for breaching his release conditions and is due to get out on Friday.

Finch said his fear about his grandson's release is if support is not put in place around Frank, "there will be a victim".

"We're dealing with a very unstable inmate who is screaming out for help," Scott Guthrie of the Transforming Justice Foundation told 1 NEWS.

"He clearly said to me, 'next time I'm released from prison I'm going to kill someone, so I can come back to prison for 20 to 25 years'."

Police told 1 News they have a full range of resources in place and will work closely with other agencies to ensure the public are kept safe.

Meanwhile, Corrections said Frank's release would be closely overseen by a multi-disciplinary team.

Their recommendation was Frank be intensely supervised for two years, have GPS monitoring and undertake a compulsory reintegration programme.