Apprenticeship agreements, including wage rates of apprentices, shall conform to the rules issued by the Minister of Labor and Employment. The period of apprenticeship shall not exceed six months. Apprenticeship agreements providing for wage rates below the legal minimum wage, which in no case shall start below 75 per cent of the applicable minimum wage, may be entered into only in accordance with apprenticeship programs duly approved by the Minister of Labor and Employment. The Ministry shall develop standard model programs of apprenticeship.