No person shall obstruct, impede or interfere with any officer, employee, contractor or authorized representative of the city, or with any person who owns or holds any estate or interest in any premises on which a nuisance exists and which must be abated under the provisions of this code, whenever such officer, employee, contractor or authorized representative of the city, or person having an interest or estate in such premises is engaged in the work of abating any nuisance as required by the provisions of this code, or in performing any necessary act preliminary to or incidental to such work authorized or directed pursuant to this code. (Prior code § 61.07.705)