A police officer needed eight stitches after trying to stop a man armed with a knife.

Police were at the Mann St Campground in Queenstown about 11.30pm yesterday on an unrelated matter when one of the attending officers spotted a man behaving suspiciously outside a cabin close by.

The officer approached the man who ran towards Thompson St, then headed west down the street refusing orders to stop.

The officer managed to grab the man's arm as he climbed over a fence on Thompson St above Brunswick St, dislodging a knife from the man's grip.

The man then fell down the other side of the fence onto Brunswick St and fled towards the Queenstown CBD.

After returning to the police vehicle the officer realised he had received two large cuts to his arm. He then found a large kitchen knife which had been dropped near the fence.

The officer received eight stitches.

Otago Lakes Area Commander Olaf Jensen said it was a serious incident involving an officer who sustained injury while performing his duty to protect the public.

"No officer expects to come to work and become injured in this way, and we want to hold this offender to account."

The offender is described as being 170cm-180cm tall. He was wearing a dark beanie, a dark, long-sleeved hoodie and dark pants.

Any information can be passed onto Detective Lisa Watt at Queenstown Police on (03) 4714800, or alternatively you can call Crimestoppers anonymously on 0800 555 111.