The convictions of three people for female genital mutilation in NSW will stand after Australia's highest court ruled the practice is illegal in all its various forms.

A mother, who cannot be named for legal reasons, midwife Kubra Magennis and Islamic sect community leader Shabbir Mohammedbhai Vaziri were found guilty of female genital mutilation offences against two girls under 10. Each was handed a minimum 11-month custodial sentence.

Shabbir Mohammedbhai Vaziri arriving for sentencing in March 2016. Credit:Daniel Munoz

The mother's two daughters, believed to have been aged about six or seven at the time, had their genitals cut or nicked in separate procedures in 2009 and 2012.

Their sentencing hearing in Sydney in 2016 heard that charges were laid after the girls told a female police officer and a social worker they had been subjected to "khatna" performed by Magennis.