Two $50,000 rewards announced on 15 March by Police and the families of missing people Nicholas Pike and Kaye Stewart remain unclaimed.
The rewards were announced for information leading to the bodies of Mr Pike and Mrs Stewart or convictions of people responsible for their disappearance or death.
The offers remain in force until July. The reward relating to Mr Pike ends in three weeks on 1 July while that relating to Mrs Stewart ends two weeks later on 13 July.
The rewards include consideration of immunity against prosecution for anyone who is not a principal offender, who is the first person to come forward with information or evidence.
With only weeks left before the reward periods end, investigators say that people who know something should seriously be considering the opportunity for closure.
If the rewards are not claimed, both cases will remain open and other efforts to solve them will continue.
Mr Pike was last seen by the wharf at Mt Maunganui at about 3.55am on 15 March five years ago. He was in the company of an 18-year-old female and two men, all from Tauranga. Mr Pike, who was 22-years-old, was the sober driver of a red Mazda 323, registration OP2767, which belonged to his female companion.
Detective Sergeant Dave Clifford who is heading the Pike inquiry says a number of people have contacted police, but more information is required to solve the case.
"We're grateful to the people who have come forward. However, someone knows what happened and is holding out. They need to think about their position and the ongoing stress caused to Mr Pike's family.
"We've been re-interviewing people originally spoken to five years ago, but we're still looking for that critical piece of information for a breakthrough."
Mrs Stewart, who was 62 when she went missing, was last seen walking in Rimutaka Forest Park on Monday 13 June 2005. The second anniversary of the day she went missing is tomorrow and it will be a difficult time for her family, says Detective Senior Sergeant Ross Levy who is in charge of the case.
As with Mr Pike's case, investigators working on Mrs Stewart's disappearance say they are grateful to people who have contacted them, but they are "still seeking a crucial piece to the puzzle".
Detective Senior Sergeant Levy says that given there were two intense physical searches at the time, a huge number of family and volunteer searches since, and that almost two years have passed with public activity and weather changes in the park, it is surprising that no evidence has come to light.
"The lack of evidence has given rise to a strongly-held belief that she has been the victim of foul play," he says
Mrs Stewarts' husband Bob Stewart says he and his daughters continue to hold hope that someone will come forward and provide closure. "We just want to know what happened to Kaye."
On announcing the reward in mid March, the Stewart family and friends spent two weeks distributing leaflets and maintaining displays around Wainuiomata to prompt people's memories.
Driver of quad bike still sought in Stewart inquiry
Police still want to identify the driver of a quad bike, possibly red and maybe towing a trailer, seen on the Forest Park Road at about 1.50pm on the day Kaye Stewart went missing.
Description of Nicholas Pike
Mr Pike is described as a Caucasian, thin build, 185cm tall (6 foot 1 inch), brown hair either shaved or close cut, hazel eyes. He is extensively tattooed and in particular has a bold lined pattern on his left upper arm and shoulder and a dog (terrier) on his back.
Description of Kaye Stewart
Mrs Stewart was 1.75m tall, medium build with greying light brown hair. On the day she went missing she was wearing a light nylon dark blue jacket, anorak style, dark tracksuit pants, a pink ribbed jersey and white sandshoes.
Information from the public
Kaye Stewart reward:
If you have any information please contact 0800 TIP OFF or 0800 691 102
Nicolas Pike reward:
If you have any information please contact Detective Sergeant Dave Clifford, Palmerston North CIB, Tel: 06 351 3852
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Media inquiries relating to missing person Kaye Stewart:
Contact Toni Barlow, Acting Communications Manager for Wellington Police
Tel: (04) 496 3464
Media inquiries relating to missing person Nicholas Pike:
Contact Detective Sergeant Dave Clifford, Palmerston North CIB
Tel: (06) 351 3852