Gwent Police are looking for 33-year-old Martin Grant who failed to return to from HMP Prescoed Monmouthshire last Tuesday.
He was convicted of robbery, threats to kill, possession of a bladed article and assault at Bristol Crown Court in October 2017.
He is described as white, 5ft 11” tall, of stocky or muscular build with brown wavy hair and green eyes.
He is not a registered sex offender.
He has links to Bristol and Birmingham.
It is believed there may be a potential risk due to the fact that the individual is no longer in the custody of the prison service.
Gwent Police has activated its operational plan with the aim of locating the individual and the prison are co-operating fully with us.
Members of the public are advised not to approach Martin and to call police on 101 quoting 2300327089, you can also message us on our Facebook or Twitter pages.
Alternatively you can call Crimestoppers anonymously on 0800 555 111 or visit www.crimestoppers-uk.org.
Controversy over £13m Hereford school expansion
Part of damaged former pub demolished
Tribute paid to man killed in bin lorry crash
Event celebrates the work of occupational therapists
Man dies after bin lorry collides with building in Leominster
Bin lorry crashes into Leominster house
Westons Cider extend Bulls partnership
Iconic Herefordshire building to be restored