In a surprise attack, one Waitemata policeman was almost rundown by a raging sheep.

The police officer turned his back on the North Shore sheep, giving it a chance to ram the officer in his legs.

In a Facebook post on Monday night police described the sheep as "medium build, with white hair that has been recently shorn".

"HAVE YOU SEEN THIS SHEEP?," the Waitemata District Police asked, above the video of its officer being rammed.

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The sheep was unsuccessful in toppling the officer. The policeman could be seen holding the sheep and removing himself from it after the sneak attack.

It was unclear what provoked the sheep.

The police were unable to say why they pulled the sheep over.

Police on Monday night would not comment about how the police vs sheep altercation started. However, a police spokeswoman said it might not have been an assault. Going from the video, she thought the sheep and officer looked to be friendly, saying he looked to be riding it rather than fighting it.