A mother from Cromwell, New Zealand, is trying to reunite with her toddler in Christchurch this week after the child was barred from coming home on a Qantas flight at the weekend.

Anna Grace is now warning users of airline websites to be careful when booking tickets for children, after her daughter Montana-Rose, 2 years and 10 months, was barred from flying home with her 14-year-old brother on Sunday.

Mrs Grace bought tickets on a Qantas flight for Hamish, 14, and Montana-Rose so they could return to Queenstown from Christchurch, where they were visiting their grandparents.