Detective Sergeant Trevor Beatson of Kaitaia police said extensive inquiries in the last few days had been made in an effort to encourage Walker to give himself up.
"It's important we find Walker and we urge him to get in touch with us so that this matter is resolved."
Walker is described as a 1.77m tall Caucasian of medium build with short, fair hair and a rough appearance.
He was wearing a singlet and camouflage shorts at the time he fled.
He has close links to Kaitaia, but he could have travelled outside the area and further afield than Northland.
Police have released a photo of Walker but say his hair is now shorter.
Kaitaia police have urged anyone with information on Walker's whereabouts to get in touch or to contact the anonymous Crimestoppers line.