Police said four people were seen dressed in camouflage on State Highway 4 about 8.30pm on Sunday, around 100m south of the Tikitiki Rd intersection with Mapara North Rd near Te Kuiti.
The group was described as one man and three others, two described as children.
"Police are now working to establish whether this is a credible sighting and are working to rule out other possible scenarios," police said in a statement today.
"A number of inquiries have been carried out over the past two days as we work to confirm the identity of the group.
"We are now appealing for anyone who saw this group, or who has information about their identity, to come forward, particularly anyone who has dashcam footage from the area at the time."
Police said anyone with information on the group, including if they were a part of it, to get in touch on 105 "immediately" and cite reference number 211218/5611.
A search has been on for Phillips and his three children Jayda, 11, Maverick, nine, and Ember, eight, since December 2021.
Their location is unknown, but police believed they were hiding out in western Waikato within the rural town of Marokopa or surrounding areas.
In October, a video captured by teenage hunters north of Awamarino showed a man followed by three children in wet-weather gear carrying camouflaged backpacks.
In the footage - which police described as a "credible sighting" of Phillips and the children - the group could be seen trekking through rough, overgrown terrain before disappearing behind a hill.
Police launched a three-day hunt using helicopters and officers on the ground, but were criticised for their slow response, with some questioning why they did not use drones, search dogs and heat-seeking devices.
The children's mother - who was estranged from Phillips - had also spoken out on the police response, pleading with the public to provide information and telling Mata Reports' Mihingarangi Forbes she had been abused by online trolls.
