In cities having over 25,000 inhabitants, unless now or hereafter otherwise provided by city ordinance or charter, officers and men of the police department shall each be entitled to a leave of absence of 1 day of 24 hours off duty in every 7, and a furlough of not less than 14 days once in each year: Provided, however, That this shall not prohibit the head of a police department from suspending such leave of absence or furlough, temporarily, as a matter of discipline, for insubordination of any officer or man employed by said police department: Provided further, That this act shall not apply in case of an emergency: Provided further, That any city affected by this act may, by a majority vote of the members-elect of the legislative body of said city, reduce the number of working days and hours and/or increase the furlough of employees affected by this act, any charter provisions to the contrary notwithstanding.