Family members of Cave Creek victims were in tears as they spoke at a ceremony in Greymouth marking the 20th anniversary of the tragedy.
Thirteen Tai Poutini Polytechnic outdoor recreation students and a Department of Conservation officer died when a DoC viewing platform collapsed into a ravine in the Cave Creek area near Punakaiki on the West Coast on 28 April 1995. Four students survived the 30-metre fall.
Among those who died in the collapse was Fleur Pawsey's brother Kit Pawsey.
Ms Pawsey told the gathering New Zealand's outdoors were safer for her brother's sacrifice, and while she wished that sacrifice had never been made, it had changed other people's lives for the better.
In an inquiry into the disaster, Judge Graeme Noble identified faults in the Department's structure following reforms and funding cuts.
Judge Noble found the platform had not been built with sound building practice, there were no building plans or specifications drawn up or looked over by an engineer, and the the work had been carried out by DoC workers, not tradespeople or carpenters.
No consent was applied for the structure before it was built. Instead, the department applied for a retrospective consent, and that was declined.
Judge Noble said the platform was never formally inspected, either during or after construction, and even if it had been inspected afterwards, it was unlikely that its fundamental flaws would have been revealed. One of these was that it was held together with nails, not bolts.
There were no warning signs for the platform indicating how many people could go on it at one time. A sign limiting numbers on the platform to five people had been ordered, and was even delivered to the Punakaiki field centre in January 1995, three months before the collapse.
But while the relevant officer was on holiday all the signs were tidied up and taken away. When he got back, the pressure of work, including acting as Field Centre manager, meant he overlooked the sign.
The memorial service was held at the Cave Creek Memorial Garden, at Tai Poutini Polytechnic's Greymouth campus.
Survivors, the victims' families, and officials including DOC director-general Lou Sanson attended.
A wreath and flowers were due to be laid by family members and officials, followed by speeches and a reading of the names of the victims.
Families were expected to visit the site in the afternoon and have requested privacy.