The chairman of a Waikato river trust has hit back at leaders of a major iwi who want the trust investigated.

Te Arawa kaumātua are concerned about the financial management of the Te Arawa River Iwi Trust which will get millions of dollars of taxpayer funding over the next 20 years.

Photo: 123rf

RNZ News has obtained a letter sent by Sir Toby Curtis and six other Te Arawa leaders to Crown ministers.

It raises concerns about the way the trust's being run and a potential conflict of interest with the trust and its chair Roger Pikia's personal business dealings.

Photo: RNZ

The trust is charged with restoring the river's health but in recent months questions have begun to surface about the way it operates.

RNZ News together with TV3's The Hui has been investigating concerns about the trust for several weeks.

A search of the Companies Office shows Tarit Ltd, the Trust's investment arm, owns 46 per cent of the shares in Ka Ora Limited, a new venture company which is in the business of health food wholesaling. Mr Pikia is a director of Ka Ora Limited, and through another company, Aotearoa Ltd, which he owns, has a 13 percent shareholding.

Mr Pikia is a director of that company and, through Aotearoa Ltd, which he owns, has a 13 percent shareholding.

Withdrawals from the trust's bank account in January this year would suggest it has invested $775,000 in Ka Ora.

Ka Ora owns more than 80 per cent of the shares in New Zealand Premium Whitebait Ltd, of which Mr Pikia is also a director.

Mr Pikia said he had no concerns about the arrangement and challenged whether the elders have the right, or are qualified, to question his business dealings.

"These kaumatua who are claiming to have concerns, our concern is they have not been appraised by the facts."

Mr Pikia said that any conflicts of interest had been declared.

"Not only is it ok from my perspective but it is also ok in terms of my fellow directors, because it's declared by the directors for that to take place."

In 2010, Parliament passed historic treaty settlements with Waikato River iwi establishing a framework for co-governance of the river.

As part of the settlement, the government gave the trust $10 million with a promise of $20m more.

Te Arawa leader Malcolm Short says the trust's money belongs to all of the iwi.

"We're all beneficiaries who look at it and just shake our heads and say what's going on here is certainly not conducive of what's expected at the trust.

"I think it's being treated as a very hot potato and ministers are a little bit shy of having a say about it," he said. Asked if they should be worried he said: "I would think so, yes, very much."

The concerns appear to have escalated when its chief executive Katie Paul took a personal grievance against the organisation.

She is no longer working from the trust offices and told RNZ News she was unable to comment. She did say her phone and computer had been disabled and her company car had been picked up by a security company.

Ms Paul has not been paid for four months.

RNZ News understands she had raised concerns about a potential conflict of interest over Mr Pikia's personal business dealings and the trust's investments.

Mr Short said the kaumatua have many unanswered questions, which is why they have tried to enlist the help of Finance Minister Bill English, Treaty Settlement Minister Chris Finlayson and Minister of Maori Development Te Ururoa Flavell.

They say the mana of Te Arawa is at stake, and they believe it has been seriously jeopardised by the actions of Mr Pikia.