MP Hone Harawira says Treaty of Waitangi Negotiations Minister Christopher Finlayson is holding "secret" meetings with iwi over water rights claims.
During Parliament's question time on Tuesday, Mr Harawira asked whether the Government has been secretly holding hui with tribes ahead of the release of a Waitangi Tribunal report this week.
Mr Finlayson said he had been meeting with iwi, but openly. He said he'd been talking to iwi about water rights since he became minister in 2008.
Mr Harawira ended the exchange by asking if he could come to the next meeting.
The tribunal will release an abbreviated report on Maori water rights and the partial sales of four state energy companies by Friday.
The full report will be released in September. The Government has previously said that it will sell up to 49% of Mighty River Power by the end September ''subject to market conditions'', though other commentators have predicted the sale might be delayed.