Police are offering a $30,000 reward for information about Yoon Sook Chun, a 47-year old Korean woman who went missing six years ago.
Mrs Chun has not been seen or heard from since she said goodbye to her two children at 6am on 18 May 2009, before leaving the family home, alone, through the front door.
In an email, she told her family she was going to Auckland for a break.
She was officially reported missing in December that year.
The police in Canterbury say the reward will be paid for information which establishes the location of Mrs Chun, or her body, and leads to a conviction for her disappearance or death.
Detective Sergeant Ross Tarawhiti said the police were reviewing Mrs Chun's disappearance.
"Mrs Chun was last seen six years ago and over that time it is also possible that loyalties will have changed," he said. "We hope that by offering a reward it will provide an incentive to someone who hasn't already spoken to Canterbury Police to come forward."
DS Tarawhiti said he hoped somebody would step up and contact the police.
"If you are Mrs Chun please contact Police," he said.
When she went missing in 2009, Mrs Chun lived in Aidanfield, Christchurch, and held both New Zealand and South Korean passports, neither of which has/have? been used since her disappearance.
The reward offer shall remain in force until 1 October 2015.
Anyone with any information on Mrs Chun's location or other information that could help the police find her is asked to contact the Canterbury Police on 03 363 7400 or visit their nearest police station.