Father Phan Van Loi told Radio Free Asia that officers resumed monitoring his activities after the five-day Tet holiday, Vietnam's New Year celebration which fell on Jan. 28-Feb. 1 this year.
"I asked them why they were blocking me from attending church services," the priest said. "I asked if they were police. Of course, I knew they were police because I had previously seen them around my house."
Father Loi said the police have tightened their watch over his house and monitored him closely for the last two months because he had spoken with people at the Thien An monastery in Hue, whose property has been subject to land grabs during the past few years.
Another reason was that he belongs to a group of three Catholic priests in Hue that the government deems to be dissidents, he said. The other two are Nguyen Van Ly and Nguyen Huu Giai.
Father Loi is an outspoken critic of Vietnam's communist government and its repression of civil society groups.
Ly, a prisoner of conscience who was arrested in 1977, 2001, and 2007 for various crimes against the state, served nearly two decades in prison. Authorities released him from jail last May ahead of a visit to the country by then U.S. President Barack Obama.
Giai has been a critic of the government's harassment of certain religious groups.