"Later that evening, the defendant's suspicions were confirmed when other family members informed her that the money was stolen by her son."
The mother went to ASB with the 40,000 yen and exchanged it for about $500 New Zealand dollars.
She spent the money, telling police she was desperate for it and later apologised for her actions.
Judge Philip Crayton said he was going to put the mother's behaviour to the test and sentenced her to come up if called upon for 12 months.
The sentence means she has been found guilty but will only be sentenced if she commits another crime within one year.
"This was a very poor judgement on your behalf. You owed that young boy better guidance and a better example," the judge said.
"You have appeared before, but a very long time ago. I hope this doesn't indicate a sign of things to come. You've got a lot to lose by the sounds of things."
Judge Crayton also ordered the mother to pay $500 reparation.
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