Mr Mncube was mauled to death at Zion Wildlife Gardens in Whangarei by 260kg tiger Abu on Wednesday.
A source close to Mr Mncube's family told the New Zealand Herald that if Mr Busch attended the funeral at the park tomorrow, he would be asked to leave.
It was understood that some family members feared the bitter dispute between Mr Busch and his mother, Patricia, would spill over into the funeral service and ruin it.
The pair's disagreement over the management of the park and over Mr Busch's dismissal is playing out in civil court proceedings, which were disrupted last week when the fatality occurred.
A discussion thread on Mr Busch's Facebook site blames Mrs Busch for the decision to exclude her son from the funeral and for apparently locking him out of the park since the attack occurred.
However, Zion spokeswoman Sara Reid said the park had not banned Mr Busch from the funeral.
"No one that I know has actually said to Craig, `Don't come'. He would need to check with the family."
The park remains closed to the public until it meets criteria set down by the Department of Labour and the Ministry of Agriculture and Forestry following Mr Mncube's death.
Mr Busch could not be reached for comment.
