Mr Busch, who was the centre of the Lion Man television series, fell out with the park's management, including his mother Patricia Busch, and was sacked last year after working there since 2006.
Evidence provided by park staff to the Employment Relations Authority (ERA) said Mr Busch had over time taken equipment used for day-to-day operations and locked it away in his own possession.
In a decision released today relating to one of a number of disputes involving Mr Busch and the park, the ERA said Mr Busch had to return items listed.
The ERA had painstakingly gone through dozens of disputed items worth tens of thousands of dollars to establish legal ownership.
While Mr Busch got to keep some things, as they were proved to be his own, he was ordered to return items ranging from a vehicle, trailers and guns to tools, fencing equipment and computers.
The wildlife park's representatives said most items were owned by Country Developments Ltd (CDL), which was set up to buy and maintain equipment on its behalf, and of which Mr Busch was once sole director.
The company was entitled to the equipment as a bailee, with the bailor being Mrs Busch.
It also said Wildlife Pictures Ltd owned filming equipment which it had a claim to, but that claim was denied by the ERA.
Representing Mr Busch, Daniel Erickson said there was no dispute about CDL owning the items as part of the overall business, but that Mr Busch had provided many of them through his own means.
The ERA said Mr Busch had to return the items listed within three days of today's decision, or within three days of returning to New Zealand if he happened to be overseas when the decision was released.
It found at least one of the items due to be returned had been sold by Mr Busch, and that left him open for a damages claim.
A decision on the issue of costs relating to a lack of access to park equipment was reserved pending determination of the claim for damages.
There is another ongoing dispute between the park and Mr Busch relating to the ownership of the lions.
