Any students who are not able to go home immediately will be looked after until 3.20pm by staff members, said the school on Facebook.
NCEA exams will continue as normal this afternoon and next week as they are set to take place in a different building.
"Our buildings are still safe, and students who are sitting exams can be reassured that they will not be at any increased risk, following the decision to close the school to junior students," the schoool said on social media.
Junior classes are likely to be cancelled on Monday.
Housing New Zealand staff were evacuated from their offices in Wellington CBD before 3pm today.
The evacuation follows HNZ staff noticing the angle of the floor on level nine of the building.
HNZ spokeswoman Bryony Hilless said the owner of the building at 80 Boulcott St arranged for an engineers' inspection following Monday's 7.8 magnitude earthquake.
"That report came back saying the building was structurally sound with some superficial plaster cracks."
Hillness said this initial assessment happened today, however staff noticed the floor once back in the office.
"The engineers have said that to get a better understanding of any damage they will need to move desks around and pull up carpet.
"To enable them to get this work underway quickly we've asked our staff to leave the office before 3pm this afternoon."
HNZ occupy levels eight to ten of the Boulcott St building. Other tenants include Wilson Parking, Eftpos NZ and the Educational Council.
CLOSED DAMAGED BUILDINGS
• 61 Molesworth, The former Deloitte building was already vacant. Concerns about the building saw many surrounding properties evacuated - • 2 Molesworth, High Court. The Wellington High Court will remain closed until further notice while structural engineers are undertaking further assessments • 2 Aitken, Freyberg House. Ministry of Defence, Justice Centre, ACC, Crown Law, and Education offices The building is structurally sound, but has suffered some water damage due to burst pipes. A plan is being developed to return people to the building next week. • 10 Mulgrave - Archives NZ. All people have been evacuated from our Archives New Zealand Building at 10 Mulgrave Street. This is a precautionary measure following a new visual report from a structural engineer on Thursday. • 1 Harbour View Rd, Statistics NZ, Mayor says building will likely be demolished. The government's will commission a technical investigation into the performance of the building and several others. • 0 Waterloo Quay, BNZ building. The Centre-Port owned building "performed well" in engineering assessments, and the company said it was with tenants and engineers on a timetable for reoccupation. The port also suffered damage to some wharves and roadways with some liquefaction and differential settlement in places. The building was damaged during an earlier earthquake. • 40 Taranaki St - Corner of Manners and Taranaki Sts has a cordon in place under the NEC building to protect pedestrians from glass. • 24 Tory St (reading carpark) Courtenay Central building and car park have been evacuated. Cordons are in place on Tory Street between Wakefield Street and Courtenay Place. Mayor says building will likely be demolished. Owned by Australian company READING ENTERTAINMENT • Shed 39, the home to the Greater Wellington Regional Council offices, is closed. The building is damaged, but structurally safe.