The fire at the Smith Street high school comes only a few days before the commencement of the final school term of the year.
Senior Sargent Maloney, who attended the scene, said at the time it was too early to know much about the cause of the blaze.
“We were called to the scene at 2:20am,” Senior Sargent Maloney said.
Senior Sargent Maloney also confirmed that B Block of Southport High School was on fire and police have since confirmed that the building will need to be demolished.
Gold Coast local Nicole Leue was first to the scene.
Nicole Leue said “It was such a shock to hear all this noise outside, so I looked outside of my bedroom window and the school was on fire,” Ms Leue said.
“I was really devastated, I was frightened actually,” she said.
“I called 000 straight away, and was told that the emergency services were already on their way,” Ms Leue said.
Twelve-year-old Southport high school student Anna Wilson and her mother Katherine Rhodes looked on as emergency services tended to the scene.
“There was a whooshing noise that woke me up, and I heard the sirens, so looked out the window and saw the flames,” Ms Rhodes said.
Student Anna Wilson was particularly upset about the event.
“The new building is right behind the fire, and that’s the junior computer lab,” Ms Wilson said.
The pair said the school had had a “rough run” this year, with a bomb threat on the campus in term two.
School principal Nigel Hughes posted a statement to social media on Friday afternoon describing the destruction of the school’s B Block as a “tragic loss” for the school community.
In the statement, Mr Hughes asked parents and children to stay away from the school over the weekend and police and emergency services would continue their investigations.
“Clearance to regain access to our school can only be provided once police and emergency services have completed their work and declared the site safe,” he wrote.
“This may take some time and we will work with authorities as we navigate our way through the next few days.
“We will put student, staff and community safety at the centre of decision making.”
Mr Hughes wrote that nothing in the damaged building could be saved, but said plans were in motion to put nine classrooms, a staff space and toilet block into the school site by early next week.
“The good news is that no one was injured and we will get everything replaced,” he said.
He said families at the school would be advised about when the school would reopen as soon as they had the information.
A Queensland Fire and Emergency Services spokeswoman earlier said seven crews worked to control the fire.
Forensic investigators are reportedly working with the fire service to determine the cause of the fire and police are interested in any suspicious activity seen in the area around the time of the blaze.