Auckland Council says it is unable to conclusively determine who damaged parts of Papakura Cemetery despite a thorough investigation.
Visitors to the cemetery last week found the children's burial site had been desecrated, with damaged mementos, shredded flowers and broken crosses strewn across the grass.
One visitor, Papakura resident Korenna Buchanan, who was at the cemetery last Saturday with her son to place flowers on a relative's grave, believed the council's maintenance crew had been responsible for the mess.
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Auckland Council head of operational management and maintenance Agnes McCormack said the investigation included interviewing the contractors involved to review their methodology and matching their timelines with CCTV footage.
McCormack said the council was made aware of the damage last Saturday, November 23.
"Our investigation has found a number of visitors were at the cemetery during the period the incident is believed to have happened," she said.
"As a result, we are unable to conclusively determine who may have caused the damage to adornments."
But the investigation found that the workmanship of the contractors were not up to the council's expected standard, McCormack said.
New measures have been put in place to improve this including replacing weed eaters with push mowers, having before and after photos taken at every maintenance and increasing the frequency of maintenance.
"We are working to contact families impacted by this," McCormack said.
"We will also continue working with our contractors to ensure our maintenance practices are of the highest quality."
Manurewa-Papakura Ward Councillor Daniel Newman, shared the proposed changes on Facebook, both on his own page and to the Papakura Community group.
"This has been a raw experience. I want the best performance outcome at the cemeteries," Newman said.
Auckland cemeteries have been damaged by both contractors and vandals in the past.
In 2017, around 170 plots at Manukau Memorial Gardens were damaged by maintenance workers and in 2015, a woman smashed headstones and left crosses strewn across the grass in Papakura Cemetery.
Earlier this year cemeteries in Papakura and Papakura South were also targeted by thieves who stole adornments from grave sites.
McCormack thanked those who had brought the damage to the council's attention, and said any further feedback to the council can be provided by calling 09 301 0101.