Huirua had banking and investment experience from working in the National Australia Bank (NAB).
The iwi had taken a conservative approach to investing until then but on Huirua's advice, it diversified into a more direct investment of funds including cryptocurrencies.
The 58-year-old was actively involved in managing large direct investments up to a value of $26 million.
He created two companies along with bank accounts for the purpose of investing in commodities, foreign currencies and cryptocurrencies.
One of the companies was named Society One NZ Ltd, chosen by Huirua to mirror the large Australian financial institution "Society One", which had an annual turnover in excess of $1 billion, and to avoid suspicion from iwi staff.
Iwi staff believed the company established by Huirua was related to the Australian finance company but, in fact, he was the sole director and shareholder of both.
Huirua then arranged for payments to be made from the iwi to the companies, then into Australian bank accounts in the names of various brokers and into his personal bank account.
In March 2019 Huirua lost his job with NAB for breaching rules regarding share trading accounts.
A total of $3.1 million had been transferred from the iwi into bank accounts and invested by Huirua through brokers.
However $2.6 million was lost in trading and Huirua used $500,000 for personal expenditure.
He did not advise the iwi of the losses.
When audit queries arose, Huirua created two fictitious investment managers, Stuart William and Lauren Ryan, to confirm payments had been made.
A hui was held on November 2, 2019, and he was quizzed why payments had been made into accounts he controlled and into his own personal bank accounts.
Huirua said he acted alone and was investing on behalf of the iwi which he was authorised to do.
He claimed he believed the iwi was investing in him and his knowledge but a run of bad luck with his "trading strategies" resulted in all the loss of $3.115 million.
In the High Court at Whanganui on Thursday Huirua pleaded guilty to six charges of using a forged document to gain a pecuniary advantage and one of carrying on a business fraudulently before Justice Rebecca Ellis.
Other charges were dismissed.
Justice Ellis convicted Huirua and remanded him, on bail, to appear for sentencing on April 1.
Not all of the iwi investments went bad, its Kaitahi As One smoothie products, made of indigenous superfoods are stocked in dozens of stores and supermarkets around the country.
