ISMAIL Belghar is believed to be the first Muslim in Australia to be granted a judge-only trial on the grounds that a jury may be biased because of his religious beliefs.

The decision in the New South Wales District Court can be revealed after Belghar, 36, yesterday pleaded guilty to detaining and assaulting his sister-in-law after she "dared" to take his wife to the beach without his permission.

The court heard, because of his religious beliefs and because he thought he had absolute authority over her, Belghar felt it "abhorrent" that his wife, Hanife Kokden, had been to the beach where she "displayed her body".

In March, Judge Ronald Solomon had granted Belghar a trial before a judge sitting alone after agreeing he may not receive a fair trial with a jury.

"The attitude of (Belghar) ... is based on a religious or cultural basis. In light of the fact there has been adverse publicity regarding people who hold extreme Muslim faith beliefs in the community, I am of the view that the apprehension by (Belghar) that he may not receive a fair trial is a reasonable apprehension," Judge Solomon said.

The Moroccan immigrant had originally been charged with the attempted murder of his wife's younger sister, Canan Kokden, 25.

The Crown appealed against Judge Solomon's ruling arguing that, if the judge was correct, every Muslim would be entitled to a judge-only trial.

Last week the Court of Criminal Appeal overturned the ruling and ordered Belghar be tried by a jury.

The trial was due to start yesterday when instead Belghar pleaded guilty to detaining Ms Kokden for advantage to intimidate and assault. He denied attempted murder and that charge was dropped.

Senior Crown Prosecutor Mark Tedeschi QC told the court the Crown would be seeking a jail term.

The court had heard Belghar, who has been married to his wife for 11 years, became aware she had been to the beach in late 2009 because her shoulders were slightly sunburned.

He rang his sister-in-law and said: "You slut, how dare you take my wife to the beach."

Just before Christmas, 2009, Ms Kokden came face to face with Belghar while out shopping with her brother at the Broadway Shopping Centre.

Belghar slapped her across the face then carried her to the railing around the car park where he held her out over it.

She was freed when her brother tackled Belghar.

Belghar will be sentenced at a later date.