At the time of his arrest Gray was growing tulips commercially at one of the properties, and had modified one of 10 refrigerated shipping containers he used to store tulip bulbs into a cannabis cultivation operation.
Dried cannabis and cannabis seedlings were also found at Gray's second property.
Following the investigation, Police alleged Gray had been involved in the cultivation and supply of cannabis for at least a four-year period.
In November 2018 Gray was sentenced to seven months and one week home detention on one charge of cultivating cannabis.
The civil proceedings regarding the forfeiture of Gray's properties was completed last month and the judgement was recently sealed.
"New Zealand Police, including the Asset Recovery Units, will target criminals involved in crime, including the sale of controlled drugs," Detective Senior Sergeant Brent Murray, of the Asset Recovery Unit, said.
"The aim is to continue to dismantle and disrupt criminal enterprises benefitting from the profits earned through crime, preventing the harm caused in the community from their criminal activities."
Crown Prosecutor Chris Wilkinson-Smith said the investigation included one of the largest forfeitures in the Whanganui region.
"It's an excellent example of local police uncovering the cannabis offending and then utilising a specialised unit such as the central asset recovery unit using financial analysis to confirm the true extent and time frame of the criminal offending," Wilkinson-Smith said.