It is understood that police officers have closed Westleaze between its junction with the B3147 and the Sun Inn pub.
It is believed to be caused by an electrical problem in the area, according to the pub.
A spokesperson for the pub has said: “Police have had to close the road from Dorchester due to an electrical issue.
“Access to the pub is unaffected from Charminster/Slyers Lane etc.”
Dorset Police have ben contacted for more information about the incident