The double-storey 4 in 1 classroom is one of the 16 refurbished classrooms opened recently.
The Moresby South Member, Justin Tkatchenko, who was at the fire site this afternoon said the classroom was set alight by a Grade 12 student.
It is alleged that the suspected student was disciplined earlier today and retaliated by burning the classroom.
Tkatchenko expressed frustration, adding the K1 million worth classroom was lost in just 15 minutes.
Principal Herman Panai, and his Deputy Philemon Geidilo, confirmed the incident occurred around 3pm today.
Mr Panai said the Grades 9 and 10 students will be relocated to other specialist rooms and labs.
Both head teachers said all teachers have been advised and will gather information to help the police and fire department with investigations.
Meantime, Tkatchenko condemned the actions of the suspected student and said the matter will be treated as an arson case.
Tkatchenko added the suspected student if found guilty will face the full brunt of the law