With water flooding their houses, people in Vasili and Kolagatla villages in Atmakur mandal dug a part of the national highway to make way for flood water.
Hundreds of vehicles were stranded on both sides. Officials were taking steps to divert the traffic via Kadapa.
Andhra Pradesh Municipal Administration Minister P. Narayana said the national highway will be restored by the evening as floods are expected to recede.
Incessant rains in the district bordering Tamil Nadu over last three days inundated several villages in Atmakur mandal. Tanks and canals in the district were overflowing, cutting off roads to the villages.
In Gudur division, at least 20 villages were cut off due to overflowing of Kaivalya river following heavy rains.
The rains and consequent floods were caused by a deep depression over the Bay of Bengal which crossed near the Tamil Nadu-Puducherry coast on November 9.
The rains damaged houses, roads and bridges and disrupted transport, electricity and communication in parts of Nellore district.