Israel's chief rabbi has ruled ultra-Orthodox Jews may shave their beards so gas masks fit properly in the event of a chemical attack by Iraq, and he urged them to carry scissors in order to shave quickly.

Jewish law forbids men from shaving, and many ultra-Orthodox men grow full beards and wear side curls.But traditional gas masks won't seal properly over facial hair and the issue had caused great anxiety among Israel's ultra-Orthodox community until Thursday's ruling by Chief Rabbi Mordechai Eliyahu.

The religious weekly Yom Hashishi on Thursday suggested ultra-Orthodox men consider acquiring gas masks designed for children because they cover the entire head.

But the Civil Defense agency has said catering to the needs of bearded men would not be possible because the gas masks are mass-produced.