A woman who says she has new information about an Auckland cold case killing says police haven't investigated her claims.

Katrina Jefferies, 22, was killed in July 2005 and her body was found wrapped in a tarpaulin in Waikowhai Reserve.

One News reported tonight that a woman says her friend claimed her own car was used to dump Jefferies' body and she told the TV network she knows who the killer is.

It was also reported the woman was "heartbroken and angry" to hear her son was forced to help with dumping the body.


She told police about the claims seven months ago, but they'd not acted on the information, she said.

"I just told the police because I want to know who murdered that girl," the woman told One News.

"To have my son involved. To have that young girl that's gone, we need closure."

Police did ask her last year about items found with Katrina's body, including a tarpaulin and yellow raincoat the woman remembered being in her mum's garage.

However, the woman said she'd never given a formal statement.

Until last year, the woman had never heard of Katrina Jefferies, she said.

Police issued a statement saying their investigation was ongoing and would soon be subject to an internal peer review.

"The review of historic unsolved cases is a standard police practice that allows for reassessment of further investigative and evidential opportunities," said the statement, released to One News.


"We remain committed to bringing the person[s] responsible to justice. We are mindful however that this remains an open and ongoing investigation, and because of this, will not be drawn on further aspects at this time."