Police are offering a $100,000 reward for help solving a 24-year-old cold case.
Angela Blackmoore, 21, was stabbed to death in her home on Vancouver Cres in Wainoni, Christchurch, on August 17, 1995.
Her two-year-old son was asleep at the time. Her body was discovered late that night when her partner arrived home from work.
Police spoke to hundreds of people at the time, but never found the killer.
"This was a horrific crime resulting in the death of a young mother with her whole life ahead of her," said Insp Corrie Parnell.
"Since Angela’s murder our focus has been on bringing the person responsible to justice, and although many years have passed that focus has not changed."
Police believe a member of bike gang the Templars MC may have been involved.
"With the passing of time allegiances may have changed and we’re appealing to anyone with information that might help, no matter how small or seemingly insignificant, to contact us."
Blackmoore had 39 stab wounds, all over her body. Police believe the killer was someone she knew, as there was no sign of forced entry.
A red car was seen briefly parked outside her house, but gone by the time police arrived. The murder weapon was never found. A bloody bootprint and fingerprint were left at the scene, but their owner was never found either.
Anyone with information should call the dedicated Operation Vancouver hotline on 0800 22 1995.
Police are expected to reveal more about the case on Saturday afternoon.