The New Jersey Constitution of 1947 (Annotated) Art. I, ¶ 9

9. The right of trial by jury shall remain inviolate; but the Legislature may authorize the trial of civil causes by a jury of six persons. The Legislature may provide that in any civil cause a verdict may be rendered by not less than five-sixths of the jury. The Legislature may authorize the trial of the issue of mental incompetency without a jury.