Police are appealing for help from the public to identify a man wanted over a bank robbery inside a busy mall.

On Saturday morning man allegedly threatened staff and took money from the ASB branch inside Glenfield Mall on Auckland's North Shore.

Talking to the Herald that day, a worker at Glenfield Mall claimed the robber was armed with a butcher's knife.

"The man was wearing a hoodie and sunglasses, with bank staff telling him to take it off before he made his way to the front counter.

"He then stood behind a woman with his arm around her neck and holding a knife, which led to money being handed over."

A local business owner told 1News the man was dressed "like a ninja".

"I don't even know how he was allowed in like that," they said.

"I saw him go back behind the counter and I was like, what's he doing? He can't be behind there."

"We understand this would have been frightening for the members of the public who witnessed this event, however we want to reassure the community we take these incidents incredibly seriously and are committed to holding those responsible to account," police said in their appeal.

"If you recognise any identifying features about the person in these images, we ask you to get in touch with us immediately.

"We also ask anyone who was a witness or has any information about this incident which may help us with our investigation to contact us via our 105 phone service or online using Update My Report.

They asked anyone with information to reference the file number 220716/9306, noting that information can also be provided anonymously via Crime Stoppers on 0800 555 111.