Police have crossed the Tasman - in the refuelled search for the killer of Arthur Easton in Auckland nearly 40 years ago

Easton was stabbed to death in his Papakura home in 1985.

Police last month offered a 100-thousand dollar reward for information leading to a conviction.

They've received about 20 calls and emails.

Detective Inspector, Warrick Adkin, says detectives had beneficial conversations with people in Victoria, New South Wales and Queensland.

He's urging anyone with information to get in touch.