Section 19: Power to refuse entry or to admit into Nigeria.

(1)
The power of an immigration officer to refuse entry or to admit into Nigeria subject to conditions. shall, unless the Minister otherwise directs, be exercised by notice in writing, and subject to sub-section (2) of this section, any such notice shall be given by being delivered by the immigration officer to the person to whom it relates.
(2) Where an immigrant who is to be admitted into Nigeria subject to conditions is a member of a group in the charge of a person appearing to the immigration officer to be a responsible person, the notice under this section shall be duly given if delivered to the person in charge of the group.
(3)
A notice refusing a person admission into Nigeria may at any time be cancelled by a subsequent notice in writing given to him by an immigration officer, and where a notice under this subsection cancelling such a notice is given to any person at any time, the immigration officer may at the same time give to that person a permit admitting him into Nigeria, subject to conditions.
(4)
Any condition specified in a notice under this section may at any time be revoked or varied by the Minister or the Comptroller-General of Immigration either by notice in writing given to the immigrant to whom those conditions apply or by order applying to immigrants of any class to whom the conditions for the time being apply.
(5)
Any notice under this section and any condition specified in such a notice shall unless previously cancelled or revoked under the provision of this Act, cease to have effect if the person to whom the notice was given again enters or seeks to enter Nigeria.
(6) An immigration officer shall have the power to refuse entry into Nigeria of any person who is not a citizen of Nigeria, if-
(a) the person concerned is a prohibited immigrant;
(b) where a visa is required, such person has no valid visa;
(c) where a resident or other permit is required as a condition of entry it has not been obtained; or
(d) on the advice of a medical inspector, it is undesirable for medical reasons to admit such a person.