Twelve ministers, 29 members of assembly and six members of council are participating in the fast amid tight security.
State finance minister Anam Ramnarayan Reddy told reporters that they are demanding the leadership to reconsider its decision July 30 decision to carve out separate Telangana state as it has hurt the sentiments of people of Seemandhra, which comprises Rayalaseema and Andhra regions.
"Andhra Pradesh can develop and prosper only as a united state. We will continue our efforts till the last minute to convince the leadership to take back this decision," he said.
Primary education minister S Sailajanath said at a time when people's protests in Seemandhra was continuing for over a month and intensifying with every passing day, they decided to be on the side of people.
This is the first time that Seemandhra leaders have taken up a fast in Hyderabad to oppose the Congress Working Committee (CWC) decision. Police made tight security arrangements at the assembly and in the surrounding areas to prevent any untoward incident.
Some ministers from Seemandhra had last week submitted their resignations to chief minister N Kiran Kumar Reddy. As the chief minister has not yet accepted them, two of them Monday called on Governor ESL Narasimhan to submit their resignation letters. The governor, however, told them that he would send their resignations to the chief minister and act as per his recommendation.