"This was a very serious assault that was extremely traumatising for our victims and that has left one man fighting for his life."
A scene examination has been completed and police are examining exhibits seized.
Two men were walking along Fergusson Drive near Caltex Rimutaka at around 8.30pm on Saturday night when they were approached by a man and seriously assaulted.
One was transported to hospital where he underwent emergency surgery and remains in a critical condition with life-threatening injuries.
The other received moderate injuries and has since been discharged from hospital.
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.
Police are continuing to investigate if the woman following them is linked to the assault, and urge anyone with information that could assist our investigation to come forward.
Anyone who was at the Caltex Rimutaka Fergusson Drive area between 7.40pm and 8.40pm on Saturday night is asked to contact Police.
Motorists passing through this area who may have dashcam 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.
