Staff at a Wellington butchery have been left dumbfounded by a thief who stole a donation box for a local charity.

On Tuesday, a man walked into Preston's butchery in Porirua and nabbed a donation box for Wellington Free Ambulance off the counter.

Security camera footage shows the man then walking around the shop before leaving with the box in his hands.

SUPPLIED CCTV footage of a man leaving Preston's Butchery in Porirua with the the donation box.

He hopped into a waiting car and drove off.

Staff were unaware the man had taken the box until a customer entering the shop notified them the man had walked out with it.

Produce manager Suzanne Downes, who was working on the till at the time, said she had her back turned when the man took the box.

She was astounded at the man's confidence to take the box, then walk around the shop before leaving.

"He was keeping an eye out where our staff were. We were filling shelves and he was holding it really obviously, just walking around with it," she said.

The man had spent time watching the staff, which was unnerving, she said.

"He was here for quite a while watching us, which is the creepy thing."

"He was really well dressed with a white shirt which ironically said, 'nobody likes a smartass'," she said.

Downes did not know how much money was in the box.

Preston's posted a picture of the man from the security footage on Facebook.

A spokesperson for Preston's confirmed two names had been given to them as result of the post, which had since been passed on to police.

Wellington Free Ambulance spokesperson Di Livingston said it was disappointing the robbery had taken place.

"It's a shame, as the shop owner is doing something great to support us, and of course, this isn't where people making donations to Wellington Free Ambulance expect their coins to end up," she said.

"Thankfully it happens very rarely. Most people are very honest and know that the ambulance collection boxes are there for a very good reason."