A rapid assessment of Orana Wildlife Park's conditions today will determine the truth of claims of poor welfare standards.

More than 20 current and former staff at the Christchurch zoo have told 1News about animal deaths, with some going unreported.

Ministry of Primary Industries staff have visited today.

Investigations Director, Gary Orr, says it's a requirement to document all animal injuries.

"But we would expect the operators to notify us proactively if there were any serious animal welfare issues - and matters that had been raised had not previously come to our attention."

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