The Gopalganj district magistrate demolished the boundary walls erected by former Bihar chief minister Rabri Devi's brother Sadhu Yadav on government land.
Yadav is a Rashtriya Janata Dal member of Parliament.
Sources in Gopalganj district administration said District Magistrate M K K Pathak had ordered demolition.
"Sadhu Yadav had attempted to encroach government land near his palatial house in Gopalganj," an official of the district administration said.
Gopalganj was Yadav's stronghold during the last 15 years when the RJD was in power in the state.
However, Yadav denied that the walls demolished by the district magistrate was on a land encroached by him.