A NSW conwoman whose seven years of scams in three continents cost charities and governments close to $700,000 has been sentenced to at least six months in jail.

Samantha Azzopardi, 28, pushed her luck too far this year when she posed as a 13-year-old Sydney high school student named Harper Hart and repeated a lie that had previously fooled authorities in Ireland and Canada.

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

Azzopardi claimed she was a child sex-trafficking victim but, when authorities investigated, they realised she wasn't what she seemed.

She pleaded guilty in June to four fraud offences.