A Sydney father has been found guilty of "procuring" his 12-year-old daughter for sex with a 27-year-old man after arranging for them to be married in an Islamic ceremony.

The father, 63, whose name cannot be published to protect daughter's identity, was convicted of "intentionally procuring a child under 14 for unlawful sexual activity" and for "inciting" and "encouraging" this activity to take place.

The man had pleaded not guilty, claiming that - although he was aware of the wedding - he had not consented to it and did not know about or consent to the sexual intercourse.

But, on Wednesday, Judge Deborah Sweeney convicted him on both counts following a two-week judge alone trial in the Downing Centre District Court.

Judge Sweeney found that, seeing his daughter had reached puberty and was becoming interested in boys, the father decided that the 12-year-old should get married because he believed that, under his religion, having sex outside wedlock was a sin.