A man has been arrested in relation to a violent attack in Queenstown in March

The complainant is also being charged with giving false information - after police established the attack was not random.

Police initially said a "Good Samaritan" suffered a fractured jaw, after an assault and robbery on the Queenstown side of the Crown Range.

They said a man signalled for help using a cellphone torch, claiming something was wrong with his vehicle.

Detective Senior Sergeant Malcolm Inglis say a 20-year-old Cromwell man has been charged with the robbery.

But Inglis says the man originally portrayed as an innocent good samaritan will also face the courts.