In case of necessity regarding workers receiving vocational training who have received recognition as provided for by Article 24, paragraph 1 of the Vocational Ability Development and Promotion Law (Law No. 64 of 1969) (including cases where the same provisions are applied correspondingly under paragraph 2 of Article 27 of that Law), the provisions of Article 14 concerning contract period, the provisions of Articles 62 and 64-5 concerning restrictions on dangerous and injurious jobs for minors and expectant and nursing mothers and others, and the provisions of Articles 63 and 64-4 concerning the ban on underground labour by minors and women may be otherwise provided for by ordinance, within the limits of the necessity; however, this shall not apply with respect to the ban on underground labour by minors under Article 63, as regards persons under 16 full years of age.