A man was critically injured and hospitalised for emergency surgery after a serious assault in Upper Hutt last night, and Hutt Valley police are seeking witnesses. 

Detective Senior Sergeant Martin Todd said two men were walking along Fergusson Drive near Caltex Rimutaka about 8.30pm when they were approached by a man and seriously assaulted with a weapon. 

One was transported to hospital where he underwent surgery and remains in a critical condition with life-threatening injuries. 

The other received moderate injuries and has since been discharged. 

The two victims had called police at 7.50pm, saying they were concerned about a woman who was following them, filming and taking pictures of them, Todd said. 

"We are working to establish whether these two incidents are linked," Detective Senior Sergeant Todd says. 

Anyone who was at the Caltex Rimutaka Fergusson Drive area between 7.40pm and 8.40pm last night is asked to contact police. 

Motorists passing through this area who may have dash cam footage or private dwellings in the area with home CCTV footage are also urged to provide their footage to police. 

Police are also appealing for the woman who filmed the victims prior to the assault to come forward and speak with them, or for anyone who knows the woman to contact them. 

Contact police by calling 105 and quoting file number 220320/3075.  

People can also contact police anonymously via Crime Stoppers on 0800 555 111. 

- by Sophie Trigger, NZ Herald