The Director, by public notice, may declare –

(a) a disease, whether communicable or non-communicable, that is specified in the notice, or all diseases, whether communicable or non-communicable, that are members of a class of diseases specified in the notice, to be notifiable diseases; and

(b) an organism, or substance, that is specified in the notice, or all organisms or substances that are members of a class of organisms or substances specified in the notice, to be notifiable contaminants.