Police have released the CCTV footage of a sustained attack on a South Auckland shopkeeper in which an offender slams him into an ice cream freezer, beats him down and then holds a large knife to his throat.

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The offenders entered the Kingsford Superette on Raglan Street in Mangere about 7.30pm on Tuesday and immediately struck the victim on the back of the head, causing him to fall forward.

Another robber held a knife to the man's throat before throwing him to the ground and holding him down.

Police dogs were brought in and it is believed the robbers left through a park and on to Haddon Street.

The male victim suffered facial and head injuries as well as bruising to his body and is recovering with family and is being supported by police.

Police are slamming the offenders, who took cigarettes from the store, as "absolute cowards".

"They are violent, dangerous and need to be held to account for what they have done," said Detective Inspector Fa'amanuia Va'aelua of Counties Manukau Police.

He hoped the "disturbing" footage would enable the police to catch the four masked men.