An Australian based fraudster has brought shame as well as a loss of mana and trust to his iwi after he conned the organisation out of more than $3 million.

The entrepreneurial South Taranaki iwi Ngā Rauru Kītahi, which created Kaitahi As One smoothie products made of indigenous superfoods and stocked in supermarkets around the country, lost $3.1m to Te Whitinga Mark Huirua's scam.

Huirua appeared before Justice Warrick Gendall in the High Court at Whanganui for sentencing on Friday after pleading guilty to six charges of using a forged document to gain a pecuniary advantage and one of carrying on a business fraudulently in February.

Huirua's whānau belong to the iwi and were held in high standing but the court heard he has since been shunned by the organisation after his offending was discovered.

Gendall said Huirua felt crushed he was no longer part of the iwi and had been cut off from his whakapapa.

The iwi had suffered a significant loss of mana and trust as a result of Huirua's offending, he said.

Huirua was sentenced to a total of two years and 11 months' imprisonment.

In its 2003 Treaty settlement Ngā Rauru Kītahi, one of eight generally recognised iwi of Taranaki, entered into a Deed of Settlement with the Crown for its historical claims which included financial redress of $31 million.

In 2016 the Sydney-based Huirua was contracted by a trust, set up by the iwi for charitable purposes, when he was appointed to the board of the company heading its investment arm.

Until then the iwi had taken a conservative approach to investing but on the advice of Huirua, who boasted banking and investment experience from working in the National Australia Bank (NAB), 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.

Bank accounts and companies were set up by Huirua for the purpose of investing in commodities, foreign currencies and cryptocurrencies.

He named one of the companies Society One NZ Ltd, chosen to mirror the large Australian financial institution "Society One" and avoid creating suspicion of iwi staff, which had an annual turnover in excess of $1 billion.

The iwi fell for it, believing the company was related to the Australian finance giant, but in fact Huirua was the sole director and shareholder of both companies he established.

He arranged for the iwi to make payments to the companies, which were then transferred into Australian bank accounts in the names of various brokers and into his personal bank account.

Huirua's scam started to unravel in March 2019, when he lost his job with NAB for breaching rules regarding share trading accounts.

He had lost $2.6 million in trading, on cryptocurrency investments, and used $500,000 for personal expenditure.

Huirua didn't advise the iwi and instead attempted to keep the ruse running by creating two fictitious investment managers to confirm payments had been made.

However, at a hui in November 2019, Huirua was quizzed why payments had been made into accounts he controlled and into his own personal bank accounts.

He claimed he had acted alone and had believed the iwi was investing in him and his knowledge but a run of bad luck with his "trading strategies" resulted in the losses.

- Leighton Keith, Open Justice