Labour MP Shane Jones says the Maori Party has put the Treaty of Waitangi at risk through its constitutional review.
Maori Party co-leader Pita Sharples and Deputy Prime Minister Bill English will lead the review, which is expected to take up to three years.
Mr Jones says the Maori Party wants to make the Treaty part of a written constitution but it needs to think through the consequences.
"Just go slow, be very careful," he said on Waatea News.
He added that the review is likely to turn into a 'three year talkfest', with any recommendations put into the too hard basket.