Officials say Bloomberg visited with protesters Wednesday to tell them of plans to clean Zuccotti Park by the end of the week.
Deputy Mayor Cas Holloway said in a statement the protest has "created unsanitary conditions and considerable wear and tear on the park."
The park is owned by Brookfield Properties, which has asked the police commissioner for help from the NYPD to clear the park so it can be cleaned.
Holloway said the cleaning will be done in stages Friday.
Protesters will have to leave, but will be allowed to return after it's cleaned.