Waikato police have turned to Facebook in an attempt to find the culprit responsible for stealing part of a State Highway 21 sign.
A photo of the sign, located somewhere between Hamilton and Te Awamutu, shows a large hole where the '21' should be.
The theft left police incredulous, with Waikato police joking in a Facebook post people could easily make their own signs for a 21st.
"What buffoon did this?" the post said.
"Seen a lot of things in my time but this? Seriously? Make your own 21st sign."
More than 150 people reacted to the post and several users commented, expressing shock or joking about the theft.
"Technically they did make their own 21st sign," one comment said.
Waikato police have asked anyone with information about how the sign was damaged to contact them.