Court documents show that between April 2, 2005 and September 18, 2011, she received an overpayment of $88,300.98. If the stay-at-home mother had advised the MSD of her true circumstances, she might have received another type of benefit, it said.
It calculated its loss at $82,789.04. Benefit fraud cost taxpayers a record $22.6 million last year, tripling from $7.5 million five years ago.
Hawke pleaded guilty in July and is facing seven years in prison on a charge of obtaining by deception, and seven years for four charges of dishonestly using a document.
Hawke was interviewed about her living arrangements on two occasions in September last year.
"She states she was aware of her obligations however had not advised of living with Dean Gregory because they were always in and out of debt, it was hard to find extra money," the documents said. "She stated she knew what she was doing, so she could give her kids a better life and did not think of the consequences."
The ministry would not seek reparations from Hawke.
"On signing the application for benefit the defendant agreed to immediately advise the ministry if there were any changes to her circumstances that may affect her entitlement to the benefit, including if she had changes to her living situation such as starting or ending a relationship similar to marriage," the documents said.
Hawke is the whangai sister of former Labour MP Joe Hawke and his brothers Grant and Alec Hawke, who led the protests at Bastion Pt in 1977.
A family member living on the same street told the Herald that she had moved to Papatoetoe but did not want to comment on the case.
The Ministry of Social Development has said it will comment after Hawke is sentenced next month.