The council made this known on its official twitter page @waecnigeria on Thursday.
The registration of the WASSCE private candidates began on October 9.
The council said candidates can obtain registration pin on www.waeconline.org.ng.
“This is to inform interested candidates and the general public that the closing date of registration for the WASSCE for Private Candidates, 2018-First Series has been extended to Friday, January 12, 2018 by 12noon,” it said.
The council had earlier announced that it will begin to conduct two series of the WASSCE for private candidates from 2018.
According to the council, the first series will be conducted between January and February while the second will be between August and October each year.
The council said candidates are expected to pay a registration fee of N13,950 and a commission of N500 to banks and accredited agents.
The West African Senior School Certificate Examination, WASSCE, is a standardised test in West Africa which is administered by the West African Examinations Council.