A former trustee of the Pārengarenga 3G Trust, a large block of forested Māori land has pleaded guilty to defrauding the amount of nearly $1 million in a Serious Fraud Office prosecution.

Margaret Dixon, 59, pleaded guilty to three representative charges of 'theft by a person in a special relationship.'

Dixon intentionally failed to deal with $934,270 of the trust's funds in accordance with the P3G trust order.

However, her big brother, Stephen Henare, 60, pleaded not guilty to six charges and is due in the Auckland District Court for a case review hearing on 23 May.

Meanwhile, his sister is set to reappear for sentencing on July 6.