If the nuisance on the property has not been abated within 14 days after the city governing body's resolution, the mayor of the city shall order the nuisance to be abated. The abatement may be accomplished, at the option of the city, by its own forces or by contract. For purposes of this subpart, compliance with the competitive bid laws shall not be required. All city employees and duly authorized agents are expressly authorized to enter private property for the purpose of abating the nuisance thereon.