South African keeper Dalu Mncube was killed Tuesday while cleaning an enclosure with another keeper at the Zion Wildlife Gardens, near Whangarei, the New Zealand Herald reported Wednesday.
The white tiger, one of only 120 in the world, was to have been put down and the park closed while police and Department of Labor staff investigate the incident, officials said.
Other zoo employees tried to save Mncube, who saved another zookeeper from a tiger attack in February, but the male tiger wouldn't release the keeper, who died at the scene from injuries to his head, torso and lower leg, officials said.
Northland police inspector Paul Dimery said the attack was being treated as a criminal investigation, but noted nothing suggested the death was suspicious, the newspaper said.
"But I'd rather be safe than sorry," Dimery said. "It's not very nice in there."
The facility and zoo co-owner Craig Busch, nicknamed "The Lion Man," is featured on the television show the "Lion Man."