The country's highest-profile suicide prevention helpline is missing one in four phone calls because of a funding shortage.
At the same time, Lifeline is dealing with a rise in phone calls by people who are at risk of suicide.
The helpline now receives an average of six calls a day from people in severe distress - double the amount it received three years ago.
Executive director Glenda Schnell said calls from suicidal people were highly complicated and consumed much more resources from the helpline, which is staffed by a combination of paid staff and volunteers.
"It's an ongoing concern for us that we have so many people calling in," she said. "And it really concerns me that we are missing people."
Some callers who did not get through left messages or were called back, but Schnell said it was critical that the organisation was able to take all callers at the first attempt.
"We know that every contact with somebody in distress is an opportunity to intervene where we need to," she said.
Lifeline will this week appeal to the public for donations to cover the costs of running the helpline. It is launching the largest fundraising campaign in its 50-year history. Called the "The 72 Club", it is a play on the "27 Club" of famous artists who died too young.
Lifeline - which also runs counselling and suicide prevention training - unsuccessfully tendered for government funding for its helpline in 2015. Rather than give the contract to an established brand, the previous National-led Government launched a new helpline called Need to Talk? last year.
But Lifeline still receives 10,000 calls and 3800 texts a month because of its name recognition and long track record.
The fully-funded service Need to Talk? gets around 2300 calls and 2500 text message conversations a month. It is part of a larger network called the National Telehealth Service, whose five mental health and addictions helplines get a total of 140,000 calls and texts a year.
The founders of the National Telehealth Service, Homecare Medical, note that it gained the contract because established brands were not resonating with young people.
Ministry of Health deputy director of mental health Ian Soosay defended the decision to fund a new service over Lifeline.
He said the establishment of Need to Talk? was part of a conglomeration of national helplines which aimed to help callers quickly no matter what issue they were dealing with - from gambling to alcohol addiction.
"This is beneficial to New Zealanders, as this was not possible when various helplines were contracted to different providers, and would mean those who needed help may have to call multiple helplines where they might receive conflicting advice or help."
Lifeline's plea for donations comes a week after it was revealed that New Zealand's suicide statistics had hit a new high for the fourth consecutive year.
Provisional statistics show 606 Kiwis took their own life in the 2016-17 year, with the number men and Maori well above national averages.
Victoria Kendall, an Aucklander who volunteers for Lifeline, said she became a helpline volunteer after her father committed suicide in December 2016. His father also took his own life at the same age, 59.
"It spooked me a bit," she said. "You almost have this irrational feeling of who's it coming for next?"
Kendall said it was frustrating for Lifeline to have uncertain funding year after year.
"[Lifeline] can never plan a year out because you never know how much funding you're going to get," she said.
"It surprised me that we have to depend so heavily on this type of fundraising."
Lifeline has also lost several other contracts in the last few years which did not directly relate to its helpline but have affected its overall ability to deliver its services. This included a contract for the Depression Helpline made famous by Sir John Kirwan.
Schnell rejected any suggestion that the organisation had fallen out of favour with the Government.
"Not at all," she said. "All businesses have contracts that come and go… We will continue to work with the [ministry] and other government departments to support the community in distress."
LIFELINE UNDER PRESSURE
• Lifeline receives 10,000 calls and 3800 texts a month from people in distress
• 6 calls a day are from people at risk of suicide
If you are worried about your or someone else's mental health, the best place to get help is your GP or local mental health provider. However, if you or someone else is in danger or endangering others, call police immediately on 111.