Someone keeps moving traffic signs and cones on the road between Desertmartin and Draperstown, according to Magherafelt PSNI.
They are appealing for an end to the practice as it could lead to a "nasty incident."
A watermain is being laid and the road has been closed since the beginning of February. It is expected to re-open on March 17 and until then diversions are in place.
Police said in a social media post: "There’s someone out Desertmartin way has too much love for road signs and cones. They keep feeling the need to move them as well as playing hide and seek with them.
"Now, if cones are your passion thats up to you but go on ebay, get some of your own and then you can move them round your living room to your heart’s content.
"The ones between Draperstown and Desertmartin need to stay where they are, there are significant trenches dug along that road and they are there to stop a nasty incident.
"We understand frustration of roadworks and detours, but really not a good idea to reopen closed roads. Liability for any incident that follows falls to whoever moved the signs."