Amber-Lee vanished on October 17, 1992 at Kingston, a small town at the southern end of Lake Wakatipu.

She was there with her mother Nicola Cruickshank, stepfather James Gill and baby brother Danny.

Despite exhaustive searches of the lake, town and surrounding bush, there has never been any sign of Amber-Lee.

Detective Sergeant John Kean said he had received a number of calls from the public after Chasing Ghosts was launched.

The calls had given him information to follow up but there was still no firm answer as to what happened to Amber-Lee.

"We've got bits and pieces, but I haven't had the magical call yet," he said.

"We're just working through what we've got, calling people back."

Amber-Lee Cruickshank went missing at Lake Wakatipu in 1992. There has been no sign of her since. Photograph supplied

Kean encouraged anyone with information to come forward, either to police or through the anonymous crime reporting line Crimestoppers.

"The public hold the key," he said.

"Someone out there must know. I know they know, I just don't know who.

"They have to come forward to the police.

"I'm not sure how anybody could live with that for 25 years and know what they know."

Detective Sergeant John Kean is the current head of Operation Oliver, the search for Amber-Lee Cruickshank. New Zealand Herald photograph by Mike Scott