According to the CODE, the offense carries up to three months in prison.
Read the section below:
Assistance by private persons called on by officers of the law
(1) Every male inhabitant of Zimbabwe between the ages of sixteen and sixty is, when called upon by any police officer, authorized and required to assist that police officer in making any arrest which by law that police officer is authorized to make of any person charged with or suspected of the commission of any offence, or to assist that police officer in retaining the custody of any person so arrested.
(2) Any inhabitant of Zimbabwe who, without sufficient excuse, refuses or fails to assist when called upon to do so shall be guilty of an offence and liable to a fine not exceeding level four or to imprisonment for a period not exceeding three months or to both such fine and such imprisonment.