Ms Reihana said Matiaha was overpaid a total of $40,452.23.
Lawyer Peter Stevens entered guilty pleas on Matiaha's behalf and said she regretted her involvement.
Judge Thomas Broadmore convicted Matiaha and remanded her to April 29 for sentencing.
In an unrelated case, Masterton's Simon James Harper, 50 pleaded guilty to a charge of obtaining by deception.
Ms Reihana said Harper changed from the caregiver's Domestic Purpose Benefit to the Unemployment Benefit in April 2010. When it was due to be renewed, Harper said he was single and the benefit resumed until November 2011.
It was found out Harper had been living with his partner since April 2010, and when he was interviewed about the matter he said it may have appeared they were a couple but weren't.
He received an overpayment of $2523.58.
Lawyer Ian Hard said Harper had lost a large part of his income when he changed benefits and was "struggling".
"He's an essentially honest person," he said. "This is just a situation which crept up on him."
Mr Hard entered a guilty plea on Harper's behalf.
Judge Broadmore convicted Harper and sentenced him to 60 hours community work. He was to repay the money at a rate of $10 per week.