He pleaded guilty in 2016 to six charges of manufacturing meth, two of conspiring to supply meth, one of possession of meth for supply, one of supplying pseudoephedrine and one of participating in an organised criminal group.
But Harding tried unsuccessfully in 2017 to backtrack on some of his pleas, arguing he'd pleaded guilty to them through a mistake of law.
At the 2017 sentencing in the High Court at Whangārei, Justice Simon Moore said it was concerning Harding had told a probation officer he didn't think being part of the gang impacted his actions.
"But even more concerning is your total lack of remorse for what you have done despite your comment that you hate meth. You insist you did nothing wrong and even more startling you're recorded as saying you'd do it all again.
"That is a breathtaking statement which unsurprisingly led the probation officer to conclude your risk of reoffending is high and your risk of harm to others is also high.
"You are not and have never been addicted. You've never been a user of the drug. This means the only reason you embarked on this exercise was to accumulate wealth."
He sentenced Harding to 28 years and six months in prison with a non parole period of 10 years, but Harding is today appealing the sentence in the Court of Appeal in Wellington.
His lawyer, Thomas Harre said Harding's sentence start point should be shortened when compared to another case where someone imported 500kg of meth into the country.
He was referring to a case from 2016, where a group of eight men collected 501kg of methamphetamine 12km offshore from 90 Mile Beach after launching a boat at Ahipara.
The meth, with an estimated street value of up to $150 million, was found by police over the next two days.
He said more allowance needed to be built into the sentencing process to create balance between a person's role in the offending, and the quantity of the drugs.
Crown lawyer Karen Grau reminded the court an error in the sentence needed to be identified for the appeal.
"There's no getting away from the fact that this was a particularly stern sentence," she said.
"It might be too cheeky of me to say that a sentence like this may have deterred people."
Justice Timothy Brewer said deterrence was "a fine word".
"When they were hanging pickpockets at Tyburn there were pickpockets working the crowd," he said.
Grau said it was "comparing apples to oranges" to draw links between a large manufacturing set up and the amount of meth that could be imported from overseas.
"To make 500kg of meth, it's not going to happen in a suburban/rural house out of Whangārei. But this is a case where the house was set up for that very purpose with people working in shifts and Mr Harding in charge of everything from getting the materials together, to getting the manufacturing right, to sending it off to Auckland to go on the market.
"He had to do a whole lot more than someone who got a few people together on 90 Mile Beach to catch a product that already existed."
In response, Harre said future sentencing judges would find assessing "leadership" in offending to be a "clunky and complex" process.
