Bags of cocaine and methamphetamine have been discovered inside a pair of shoes during an inspection of incoming property at Rimutaka Prison.
Department of Corrections released a statement on Wednesday, stating a detector dog discovered the pair of shoes during a routine check.
"Detector Dog Bart was spot on when he became shoe-spicious of a box during a routine search of incoming property at Rimutaka Prison earlier this month," the statement read.
"During the search, Bart gave a very strong indication on a box of trainers. He would not leave the box alone."
The dog's handler, John Thorne, then searched the shoes and inspected any unusual cavities. However, he didn't locate anything concerning.
"Bart was adamant that he was right, so I knew I needed to keep searching," Thorne said. "I checked the padding around the heel and then I felt an inconsistency."
"I ripped open that cavity and found a bag of white powder," he said.
"I then felt the padding on the other side of the shoe, and I felt a similar inconsistency. I checked the other shoe, and it was the same on both sides."
The incident was immediately reported to police and the substances were collected to be tested.
"Police have since confirmed the contraband as two small bags of methamphetamine (approximately 2.5 grams total), and four larger bags of cocaine (approximately 22.5 grams total)."
Thorne said he trusted his dog and "couldn't accept that there was nothing there".
"Let this be a clear message to anyone attempting to bring in or send any contraband to our sites - you will be caught," he said.
"There is no place for drugs in prison. They create a more dangerous working environment for our staff, and prevent prisoners from engaging in rehabilitation, education and employment opportunities."
Corrections confirm they are "constantly working to stay one step ahead of new methods used to introduce contraband into our prisons".