Craigavon Senior High School's Portadown campus is to temporarily close after a cluster of Covid-19 cases at the school.
Pupils with be taught remotely.
Students were encouraged to get a test over the weekend at a mobile testing unit that was sent to the school grounds.
Sky News reported that 48 students had tested positive in the space of four days.
The Principal of Craigavon Senior High, Ms Ruth Harkness, told BBC News NI confirmed a cluster of Covid-19 cases "within the school community" but would not specify how many.
"Following testing, a number of positive cases have been identified and these individuals are required to self-isolate for 10 days," she said.
"All close contacts of positive cases will be required to self-isolate for 14 days."
She added: "Due to the complexity of this situation and following PHA advice, the school, in conjunction with the Education Authority has decided to make a temporary move to remote learning."
"This will allow teaching of pupils to continue in a safe environment."
Craigavon Senior High School has about 600 pupils, all of whom are in year 11 or year 12 becasue children transfer at age 14 from junior high schools in the area.
The school's Lurgan campus will remain open.
As we continue to work with the PHA we would encourage all our students from the Portadown Campus to take the... Posted by Craigavon Senior High School. on Sunday, November 15, 2020
