Bolton Equities, which is based in Remuera, Auckland, but has land holdings in Northland, bought the business from previous owners Earth Crest in mid 2014 and the place is being upgraded to meet new rules around animal enclosures.
The park was also formerly owned by TV's Lion Man, Craig Busch.
It is understood health checks on all 27 big cats started this week and will run over the next three weeks.
Dr Lisa Argilla is leading the health checks.
"Lisa is helping us to make sure we bring this place forward, we are all very excited to see the park heading in the right direction and look forward to sharing it with everyone," the sanctuary said on its Facebook page.
Park owners are publicly requesting donation of blankets and large towels for the comfort of large cats when they recover.
Those wishing to donate can drop them off at the New Zealand Home Loans' office on Rathbone St in Whangarei.