The family of zoo keeper Samantha Kudeweh are upset Hamilton City Council took so long to take responsibility for the mum-of-two's fatal mauling by a tiger.
They also say warning signs were missed after a tiger had a close encounter with another staff member in 2013.
Hamilton City Council on Thursday admitted one charge in relation to Ms Kudeweh's killing by 11-year-old Sumatran tiger Oz, on September 20.
Council chief executive Richard Briggs says the council was sorry for the tragedy.
"Health and Safety is my responsibility as chief executive, and I take that responsibility extremely seriously.
"Council's guilty plea today recognises that the practical steps, as outlined in the Worksafe prosecution, were not taken, and as a result, Sam died. We take responsibility for this."
The keeper wasn't supposed to be in the cage with the tiger when she was attacked.
In March, WorkSafe NZ, police and Ministry for Primary Industries (MPI) charged Hamilton City Council for failing to take practical steps to ensure the safety of Ms Kudeweh while working with Oz.
Council deputy chief executive Lance Vervoort says Hamilton Zoo has always complied with MPI zoo regulations.
"Our own investigation revealed that human error occurred on the day Sam was killed, but we will never be absolutely sure what actually happened, and why that happened.
"Our engineered systems and keeper procedures were not adequate in keeping her safe when the circumstances arose on that day of the accident, that's why we have pleaded guilty to the charges."
The charge was brought under the Health and Safety in Employment Act, and carries a maximum fine of up to $250,000.
But Ms Kudeweh's husband Richard Kudeweh says the fine "doesn't do a lot for the family".
"I've lost my soul mate, my wife."
Mr Kudeweh says the time since his wife's death has been the most difficult nine months of his life. The couple have two children, who were nine and three at the time their mother died.
"There's no amount of anything that the council can give to us that's going to make any significant difference in terms of bringing Sam back, because that just can't happen, but we accept that," Mr Kudeweh said outside court this morning, where he was supported by other family members.
"Today the people responsible for the Health and Safety breach that ultimately killed Sam have been made to take responsibility.
"Hamilton City Council leadership, who are ultimately responsible for the Health and Safety breach, could have owned that responsibility in September 20 last year.
"They haven't, and in turn have done so much more damage to us."
Mr Kudeweh says a red flag should have been raised in 2013 when a tiger caught up with a keeper through a number of gates.
"This should have been a major, major wake-up call. Every effort at that point should have been made to make sure that situation didn't occur again. It wasn't, and Sam was killed."
He says the family have been dragged through a prolonged process unnecessarily because the council didn't own up sooner.
"That's 12 months that we didn't have to fully participate in, the responsibility should have been to look after the family.
"A guilty plea is just another step, I guess."
Mr Kudeweh says he will participate in a restorative justice process with the council.
He doesn't blame Oz the tiger and doesn't wish for him to be killed.
"I just urge zoos to take a better look at those safeguards for the keepers but also for the public. The same rules should apply to all zoos in this part of the world, and all zoos that want to function."
Ms Kudeweh's mother, Judy Stevens, says the highest priority should be the safety of zoo staff.
"This tragedy, we lost our lovely Sam, because the processes were not conducted properly. Sam should have been safe at work. That's the highest priority of any employer, and that's not the way it panned out in the end."
It's understood the council held a closed-door meeting last month to determine how it would plead, though it was kept secret.
Mr Vervoort says since Ms Kudeweh's death, the council has done "everything practical and within our knowledge to improve safety of staff who manage these dangerous animals".
This includes installing mechanical interlock devices between the personnel entry gate and the last gate, shifting the double-entry gate to the last shoot, painting the counterweights more visible and erecting signage around the service area and enclosure.
CCTV system has been installed, and two-keeper system has been implemented.
Mr Vervoort says the council will continue to monitor and review these changes.
The council will be sentenced in September.