He alleged those who managed to buy the tickets defected to the ruling Telangana Rashtra Samithi (TRS).
"If you give tickets to those who have money this is what will happen," said Rao while speaking at the hunger strike launched by Congress Legislature Party leader Mallu Bhatti Vikramarka against the "undemocratic" merger of 12 Congress MLAs with the TRS.
The former Rajya Sabha member made the remarks in the presence of All India Congress Committee in-charge of party affairs in Telangana, R. C. Khuntia and leaders of other parties supporting the hunger strike.
When Khuntia tried to stop him, Rao said nobody can stop him from speaking the truth and continued with his speech, targeting the leadership.
"When you give tickets to those who have Rs 10 crore or Rs 20 crore, they will betray the party. Recognise the party workers. Give tickets to them. They will carry the party's flag high but you have forgotten the workers," said Rao, who is known for his outspokenness.
"Those who have defected they should never be taken back in the party. You suspend them one day and take them back the next day. How long will this drama continue? We have to correct ourselves and unitedly fight TRS," he said.
Rao had earlier claimed that Congress had some 'coverts' (secret agents) who were leaking party information to TRS President and Chief Minister K. Chandrashekhar Rao.
The senior leader's latest comments came amid growing criticism in the party over the style of functioning of Khuntia and state Congress chief Uttam Kumar Reddy.
Former central minister Sarve Satyanarayana was suspended after he had openly attacked Khuntia and Reddy blaming them for the party's defeat in the Assembly election.
The Congress party, which won 19 seats in 119-member Assembly in the elections held in December last year, plunged into a crisis with the defection of 12 MLAs to the ruling TRS.
Following a request made by the group of 12 MLAs, the Assembly Speaker on Thursday recognised their merger with the TRS.
This has reduced the Congress strength to just six and the party is in danger of losing the status of main opposition party as All India Majlis-e-Ittehadul Muslimeen (AIMIM), an ally of TRS, has seven legislators.
( With inputs from IANS )