A New South Wales man who allowed his 12-year-old daughter to illegally marry in an Islamic ceremony has been sentenced to at least six years in jail.

The 63-year-old, who cannot be identified to protect the girl's identity, was convicted in April of procuring his daughter for sex with a man, who was 26 at the time, and being an accessory.

Judge Deborah Sweeney said they were serious offences which cannot be excused by the man's Islamic faith and the sentence needed to deter others from similar conduct.

The girl, now 13, was married to a 26-year-old man in a ceremony by a local sheikh at the family home in the Hunter Valley last year.

She miscarried after falling pregnant and the man she unlawfully married, now 27, has already been jailed for at least seven-and-a-half years.

Judge Sweeney said the man "failed in his duty as a father to protect his daughter".

The court heard he viewed the marriage as a solution to the risk of his daughter committing sin and allowed the ceremony to go ahead, against the wishes of the child's mother.

She described his actions as a breach of trust.

Judge Sweeney said he "lacks insight into his offending".

She imposed a total sentence of eight years for both offences.

With time already served, the man, who has been an unemployed disability pensioner for the past 20 years, will first be eligible for parole in November 2020.