A Linton army sergeant abused his authority when he assaulted a soldier who yawned during a morning roll call, a court martial hearing has been told.
Sergeant David Thomas Peachey, 26, was demoted after pleading guilty to two counts of ill-treating a person of a lower rank, the Manawatu Standard reported.
Peachey headbutted and kicked the soldier who angered him by yawning at the morning parade at Linton Army Camp on September 23, last year.
The assault resulted in the soldier receiving three stitches to his head.
Prosecutor Captain Rebecca Adamson said Peachey had taken advantage and abused his authority as a senior non-commissioning officer.
Defence lawyer Paul Murray said Peachey was remorseful and took responsibility for his actions.
The father-of-two had served in Afghanistan, East Timor and the Solomon Islands, and has no previous convictions.
The military board of the court martial demoted Peachey two ranks from sergeant to lance corporal.