The Parole Board said in its most recent decision, in November last year, that Macdonald's "significant personality disturbance" made him an undue risk to the community.
Macdonald was sentenced in September 2012 for a crime spree targeting neighbouring Feilding farms.
He pleaded guilty to six charges, including vandalism of a new house that Scott Guy and and his wife Kylee were building, the slaughter of 19 calves with hammer blows to their heads, the theft and killing of two trophy stags, emptying a neighbour's main milk vat of about 16,000 litres of milk worth tens of thousands of dollars, and burning down a 110-year-old whare.
The charges were not revealed to the murder trial jury, partly because they would have been prejudicial.
