A truck has crashed into a Manawatu RSA, and not for the first time.

Traffic is backing on State Highway 1 in Bulls, where a truck has jack-knifed into the town's RSA.

High Street has been closed as a result, with detours in place.

Police say it's lucky the vehicle's two occupants have not been injured.

The truck, carrying two trailers, has demolished the outside veranda - leave the awning hanging off the side of the building.

Bulls RSA Treasurer Craig Stevens said it's devastating.

"It's about the 4th time our building has been crashed into by trucks."

"The last time a truck hit, the driver actually got killed, this time thank goodness no one has been hurt."