Police investigating an incident which left a man in critical condition are appealing for information from the public.

A meter reader was found with serious head injuries on Oliver Street in Kihikihi, Waikato, on January 5.

Detective Senior Sergeant Andrew Saunders says he remains in a critical condition in hospital.

As part of ongoing inquiries, police are interested in hearing from members of the public who were in the carpark area of the Kakepuku Track, between the hours of 4.30pm and 5.30pm, on Thursday, 5 January.

The investigation team is particularly interested in any sightings of the victim's vehicle, a red Daihatsu Terios, registration LKN281, and a silver Nissan Primera, registration DHA220.

"We are interested in the movements of both vehicles and in identifying any occupants, as we believe they may be able to assist our enquiry team," says Andrew.

"If you have any video footage or photographs taken on the day we would also like to hear from you.

"We urge anyone with information to please get in touch with Police.

"Police want to thank the members of the public who have come forward with information and assisted with the investigation so far.

"Our enquiries are ongoing and we are determined to hold the person(s) responsible to account."

Information can be provided via 105 or Crime Stoppers anonymously on 0800 555 111, quoting file number 230105/8487.

Police would also like to hear from anyone who saw this vehicle in the area at the time.