Just before midnight last night Police and ambulance officers were called to a residential Fitzherbert Street address in Featherston.
A 40-year-old man has been taken to Wellington Hospital in a critical condition after a serious assault.
He has subsequently died shortly before 5.00am this morning.
Wairarapa Police have now launched a homicide investigation.
The residential address has been secured and a scene examination will begin with ESR scientists this morning.
A Post Mortem exmaintion will be conducted in Wellington tomorrow.
Police are appealing for anyone who may have been in the area last night to make contact with Wairarapa Police on (06) 370 0300 with any information they have.
Police are particularly interested in hearing from anyone who has seen people or vehicles acting suspiciously in the area.
Alternatively, information can be provided anonymously through Crimestoppers by phoning 0800 555 111.
ENDS
For media queries, please contact Nick Bohm, Wellington District Communications Manager on 027 559 2235.
Please note that the inquiry team has asked not be contacted as they are very busy with inquiries.
A further update will be provided at approximately 2.00pm.