A serial conwoman who posed as a 13-year-old Sydney foster child received nearly $20,000 worth of services from the NSW government and charities before she was found out, a court has heard.

Samantha Azzopardi has previously duped authorities in Ireland and Canada into thinking she was a child sex abuse and trafficking victim, forcing them to spend hundreds of thousands of dollars investigating her claims.

Samantha Azzopardi pretended to be a 13-year-old Sydney high school student named Harper Hart. Credit:Calgary Police

The 28-year-old was arrested at the beginning of June after she repeated that same story while pretending to be a 13-year-old Sydney high school student named Harper Hart.

Azzopardi pleaded guilty to four fraud offences earlier this month after she was given an iPad, phone and Opal card from the not-for-profit Burdekin Association, an ambulance transfer paid for by Good Shepherd Australia, and medication from the NSW Department of Family and Community Services.