Justice Davidson also said the case had "a striking feature".
"Apart from the cocaine identified in the supply charges [laid after his first arrest] none of the cocaine alleged to have been imported by Mr Dixon has been located by the police," the judge said.
A police summary of facts further stated that the amount of money wired overseas by Dixon "potentially sourced up to 35 kilograms of cocaine".
Dixon took his case to the Court of Appeal to challenge his sentence of 14 years and six months' imprisonment and said the judge was wrong to find he'd imported any more cocaine than admitted.
He also argued at the appeal hearing on March 8 that the judge could not conclude that anything more than 1.3kg of cocaine had been imported and wanted his sentence reduced to about 11 years behind bars.
However, he said, if his appeal were to fail the sentence imposed on him was appropriate.
In April 2015, Dixon was first sentenced to seven months' home detention and 150 hours' community work after a small amount of drugs was found on him at Auckland International Airport.
The 97.5g of cocaine packed in a condom inside Dixon's boxer shorts was discovered by Customs officers when he returned from a trip to South America on March 29, 2014.
He was arrested just months later, as part of Operation Hook, when police claimed Dixon was involved in a much wider cocaine importation operation.
He admitted making contacts, while in South America, with people involved in the Colombian cocaine trade, the court heard at his sentencing last May.
The Crown also used evidence from a Tokyo-based Drug Enforcement Administration (DEA) supervisory special agent who said Dixon sent about $152,000 in wire transfers from New Zealand to pay for Colombian cocaine.
Dixon admitted the currency transactions, mostly through Western Union to Hong Kong and Panama, which was sent to people with Colombian passports.
After his arrest in July 2015 he said he made the transactions because he was investing in US currency, and the money was for friends travelling through South America.
The UK-born man was also caught handing over US$70,000 ($101,000) to an undercover police officer at Christchurch's Hagley Park on March 16, 2015 - when he was serving his home detention sentence.
Another suspicious trade was the arrival of a FedEx package from Maracaibo in Venezuela, close to the border with Colombia.
The 10kg package labelled as "a submersible pump" arrived in New Zealand on June 15, 2015, and was delivered to Rakaia in Canterbury.
The Crown alleged various communications associated with the delivery involving Dixon indicated that it contained cocaine. However, police never found the package.
Justice Davidson said at Dixon's sentencing that Dixon had little difficulty sourcing drugs.
Text message conversations with a Colombian supplier also included references to "hat tricks" and "scoring a goal", which Justice Davidson described as "naive, futile and useless".
"One wonders why you bothered with such a code," the judge said.
In dismissing Dixon's appeal, Court of Appeal Justices Denis Clifford, Simon France and Christian Whata said they were satisfied there was sufficient evidence for Justice Davidson to be sure Dixon had imported at least 6kg of cocaine.
"We acknowledge that the judge was not in the position to reach a conclusion as to a specific amount of cocaine involved. But in our view, it clearly was a significant amount," the judges added in their decision released yesterday.
