"It is deeply disappointing ... New Zealand Police continue to use such sensationalism, misinformation and misreporting in an obvious attempt to undermine all the good works and positive community support we have worked hard to achieve," said Fatupaito.

The individual whom the police referred to as the "senior member" of the Waikato chapter - but Fatupaito is adamant has not been involved for a "number of years" - is heavily involved in the powerlifting scene.

Police allege this "senior member" of the Waikato Mongrel Mob was caught in a drugs operation, although the gang's leader says he left "years" ago. (Photo / Supplied)

With a Mongrel Mob Waikato insignia tattooed across his back, social media posts show the 33-year-old was affiliated with the chapter as recently as February 2019.

Asked why the man was no longer a member of the Waikato chapter, Fatupaito told the Herald he was unable to comment for legal reasons given the Operation Kingsville prosecution.

However, he went on to say "there have been members who had to surrender their patches and are no longer members because they hadn't stuck to Kingdom's code banning involvement in illicit drugs".

The 33-year-old faces charges of money laundering, participating in an organised criminal group, possession of methamphetamine and a glass pipe, as well as possession of anabolic steroids.

Asked about Fatupaito's assertion that none of his members were arrested in either Operation Kingsville or Operation Typhoon, a spokeswoman for the New Zealand Police said: "We stand by our previous statements."

In his open letter to police, Fatupaito said the police has had a "fractious" relationship with different chapters of the Mongrel Mob over many decades, so the police should know the individual chapters are often insular and self-governing.

"Perhaps this is a deliberate ploy to obfuscate what the Mongrel Mob Waikato Kingdom is trying to achieve. Police have negative attitudes and negative narratives that are obstructive to us and our determination to change our lives for the better," said Fatupaito.

"But still we are continually painted by your media section with the same brush as you would other organisations within the Mongrel Mob."

However, propaganda is exactly how the police view the Waikato chapter's community outreach initiatives, according to a police intelligence report released under the Official Information Act.

"New Zealand Adult Gangs are expanding recruitment by promoting the 'glamour' of gang membership as well as an outward shift towards pro-whānau and pro-community outcomes," the July 2019 report says.

"Mongrel Mob Waikato continue to use their public relations machine to raise support, recruit and spread their clean image and their pro-community intentions."

Dr Jarrod Gilbert, the author of Patched: The History of Gang Life in New Zealand, has previously told the Herald he has never seen anything like the Waikato Mongrel Mob.

He believes Sonny Fatupaito and his fellow leaders are genuine in their desire for change.

"I might be proven a fool here but I'm prepared to bet as we stand now - with the right to reserve changing my mind in the face of superior evidence - I have no doubt about that whatsoever," said Gilbert.

"I don't think they're masterminding any nefarious PR strategy. However, does that mean among the hundreds of members are there people dealing drugs? Of course there are."