Detective Mike Deegan said the robber was wearing dark clothing and had a white bandana cloth covering their face.
The person was wearing navy and white shoes, which police hope will help someone recognise them. "We are providing support to the victim who has been left shaken from this vicious and callous attack.
"It is vital that we speak with anyone that may have any information about this incident and we have released some CCTV images in the hope that the public may be able to help us identify the offender."
Police are continuing to speak with the victim in an effort to gain description details of the offender, including gender.
Police want to speak to anyone that was in the area around the service station between 3:30am to 4:15am and noticed any suspicious activity or vehicles.
Anyone with information is asked to contact Detective Constable Joe Pointon on (06) 210 2219.
Information can also be provided anonymously to the organisation Crimestoppers on 0800 555 111.