A Lebanese man was "determined" to marry a 12-year-old girl he saw in a mosque, despite being told it was illegal.

The 27-year-old, who cannot be named for legal reasons, was sentenced to a maximum 10 years' jail in the Downing Centre District Court on Friday, after pleading guilty to the persistent sexual abuse of a child.

Judge Deborah Sweeney said the man, who arrived in Australia on a student visa in June 2013, asked two religious leaders at a Hunter Valley mosque to arrange the marriage. They declined, clearly telling him it was illegal.

Undeterred, the man embarked on a "determined and deliberate pursuit of the girl" and with the help of one of her relatives, organised for a ceremony to take place at a private home on January 12, 2014.

In setting a non-parole period of seven-and-a-half years, Judge Sweeney said "neither his cultural or religious beliefs excuse his offence".