"Emergency services attended the scene quickly, however Mr McKelvie died from his injuries in hospital.
"Police are now urging anyone with information to come forward."
Todd said police believe friends or associates of McKelvie may hold information that could help in this investigation.
"We would like to hear from anyone who spoke with him in the days before his death," Todd said
"We would also like to hear from anyone else who may have information that could help our inquiry."
Anyone with information is asked to contact the police via 105, quoting file number 221015/8888, or anonymously via Crime Stoppers on 0800 555 111 or online via www.crimestoppers-nz.org.