Wellington Police are seeking witnesses to a serious assault this morning in Moera, Lower Hutt. 

Detective senior sergeant Martin Todd said police responded to a report of five or six people fighting on Trevethick Grove at around 2.15am. 

"On arrival, one man was located unconscious and had lost a lot of blood. He has received medical treatment and does not have life-threatening injuries." 

At the same time, an 18-year-old man was taken to Hutt Hospital by his friends with critical injuries, Todd said. 

The man has undergone emergency surgery and is currently in Wellington Hospital. 

"Initial inquiries indicate there was a party at a Trevethick Grove address the men had attended prior to being assaulted." 

Police would like to speak with anyone who attended the party or any members of the public who were in the vicinity of Trevethick Grove, Whites Line West and Ludlam Crescent, Lower Hutt at around 2.15am. 

"We are also asking that residents of this area check their properties for any items that do not belong to them and that may have been involved in this offending." 

A scene examination is continuing at Trevethick Grove today. 

Anyone with information that could assist Police with inquiries is asked to contact 105 and quote file number 211218/4047. Information can also be passed on anonymously by contacting Crime Stoppers on 0800 555 111.