Cost-cutting ultimately claimed zookeeper Samantha Kudeweh's life when she was mauled by a Sumatran tiger, according to a WorkSafe report into her death.

Hamilton Zoo was critically understaffed and changes made to a gate system on the tiger enclosure where Kudeweh was killed in 2015 contributed to the tragedy, the report said.

The crucial change, installing a two-gate airlock system and repositioning the keeper gate following a near-miss encounter between another keeper and tiger in 2013, meant Kudeweh, 43, could not easily see the tigers' exit gates were open.

And simple changes including painting sliding-gate counterweights a bright colour could have saved Kudeweh's life, but the paint was deemed too expensive to buy, according to the report - released to the Herald under the Official Information Act.

Moving the keeper gate was chosen over realigning the fence because that would cost too much and the report found the Hamilton City Council-owned zoo had a dangerous staffing ratio of one keeper per 21 animals, compared to one per seven at Auckland and Wellington zoos.

It also found those low staffing numbers meant zookeepers were attending to the most dangerous animals, tigers and chimpanzees, alone instead of in pairs.

Staff felt it was a matter of time before an accident would happen.

Hamilton Zoo Sumatran tiger Sali was involved in a near miss with a zookeeper in 2013. Changes made after that incident contributed to Samantha Kudeweh's death. (Photo / Christine Cornege)

Kudeweh, a mother-of-two young children, was killed on September 20 2015 when she entered the enclosure of one of two Sumatran tigers without realising he was not secured.

She went in to cut bamboo for the red pandas because the zoo was trying to reduce food costs by using its own vegetation.

However, on that Sunday morning there was a torrential downpour and she was wearing wet weather gear, something she rarely did.

It was suggested that adult male tiger Oz was not used to seeing keepers dressed in full wet weather gear and mistook Kudeweh's dark, shiny wet clothes as a mussel buoy, his favourite toy.

Kudeweh, one of the country's most experienced tiger keepers, was attacked from behind and her equipment knocked from her hands.

She was found deceased, with Oz sitting beside her body, a short time later by another keeper who could not raise her by radio or phone.

The report said the zoo had explored painting the counterweights of the sliding gates in a "cat chute" to distinguish them from the grey gates so keepers could see at a glance whether the gates were open or shut, but determined the paint was too expensive.

Repositioning the keeper gate meant keepers no longer walked past the cat chute, and this also contributed to Kudeweh - who followed procedure to a point that day - not realising Oz was not secured.

The gate was repositioned instead of the fence being realigned to allow for the new airlock system, after moving the fence was deemed too costly.

"This has been highlighted as a major component to this tragedy by a number of experienced zookeepers."

Samantha Kudeweh's death could have been prevented, a WorkSafe report has revealed. (Photo / Supplied)

Keepers interviewed by WorkSafe said the zoo was "critically understaffed and under-resourced and had been that way for many years".

The fact that both incidents happened on weekends, when less staff were rostered on, was also noted.

Zoo director at the time Stephen Standley told WorkSafe he had advised Hamilton City Council that with the current staffing level an accident was more likely.

But when interviewed HCC business general manager of community, Lance Vervoort said he was not aware of staff shortages and believed staff levels were adequate.

"He stated that if the zoo had concerns with its staffing numbers it should have brought this to the attention of senior management."

Vervoort also felt a 30-minute response time for a gun handler to arrive on site in case of an emergency was not too long.

However, the report said steps could have been taken to avoid the tragedy including:

• Employing sufficient staff to ensure a two-keeper system with dangerous animals;
• Fitting mechanical interlock devices to the gates at the tiger enclosure to prevent the keeper gate being opened if the sliding gates in the cat chute were all open;
• Leaving the keeper gate at its original location;
• Using CCTV inside the dens;
• Painting the counterweights on the cat chute sliding gates.

WorkSafe prosecuted Hamilton City Council for the safety failures and the council was fined $38,250 in 2016 and ordered to pay more than $10,000 reparation to Kudeweh's children, Billy and Sage who were just 9 and 3 when she died.

Her husband, Richard Kudeweh, who was also a zookeeper at Hamilton Zoo, told the Herald at the time the reparation, which amounted to $19.93 for each child a week over five years, was a farce.

Hamilton Zoo implemented a number of safety changes following Kudeweh's death including introducing a two-keeper care system for Sumatran tigers, painting the counterweights, and moving the keeper gate back to near the cat chute.