Over 500 Reddit users have weighed in on the authenticity of the note.
"The stamp really makes it legit. No stamp, I would have thought it was fake. One more week for sure," one wrote.
"Like every layperson just has authoritative stamps lying around. Has to be legit," another agreed.
Others confessed to their own childhood attempts at forgery.
"I did something similar as a young kid, and thought I was so clever. I signed my teachers name at the bottom and everything," one man said.
"My mom read the letter, then asked me if I would do her a quick favour. She asked me to go grab the dictionary and look up the definition of "forgery". I'd never felt so defeated in my life."
One mother who came across the post admitted she took an extra day off with her son after he presented her with a similar letter.
"I took the extra holiday (only 1 day not a whole week) to take him to the doctor to get his updated immunisations done," she said.
"He got to spend 4 hours sitting in the waiting room, got his shots, and then got home right as the unfortunate kids that weren't granted a holiday were getting off the school bus. He learned his lesson."
- nzherald.co.nz