The ministry still wanted her to serve a term of imprisonment and said although she could get some credit for previous good character she should not get any discount for remorse as a pre-sentence report found she had none.
While Judge Connell agreed not to send her to prison, he said he was only doing it for the sake of her two children who had "complex medical needs" and relied on her for their care.
"To take you away from them despite the wrongdoing, it would not be just and would not be right for them. It's my concern for them that home detention must be the sentence imposed.
"You're not remorseful, you show little insight into your offending. There is in effect a sense of entitlement in all of this from you and it was evident in the way that you gave your evidence. It seemed alright for you to lie to the court and I was less than impressed with the approach you took with all of this."
Judge Connell said it was a "combination of a number of factors" that led him to find her guilty and determine that she was living in a relationship in the nature of marriage with her partner despite her evidence to the contrary.
"I rejected your evidence because to me much of what you said during the course of it was untruthful.
"Quite clearly you were completely devoid of any honesty when you continued to claim these benefits and these other allowances.
"There are controls in place to limit the offending but it is basically a system of trust and in this case you have severely breached that trust."
Millen was sentenced to 10 months' home detention and ordered not to possess or consume any drugs or alcohol and undertake any courses as determined by her probation officer.
Judge Connell added that her sentence would be judicially monitored, meaning he would be checking in on her progress and if any issues were discovered she would be put behind bars.