DMK working president MK Stalin said the AIADMK regime in the state was trying only for a "temporary solution" to get exemption from NEET "at least for this year."
He also accused the state government of bowing before the Centre.
On a day when Chief Minister K Palaniswami met Prime Minister Narendra Modi seeking exemption from NEET, Mr Stalin, also Leader of the Opposition in the assembly, said government should not try for a temporary solution by "pledging" the state's rights.
"This is against the spirit of bills adopted in Tamil Nadu Assembly which were aimed at a permanent solution," he said in a statement.
Two bills had been recently adopted in the Assembly, envisaging continuance of under graduate medical admissions on the basis of 12th standard marks, in an attempt to come out of the purview of the National Eligibility and Entrance Test (NEET).
DMK has been targeting AIADMK on this issue, alleging that the government has betrayed the interests of students.
Mr Stalin sought to know why the Centre should hold examinations for admitting students to state-run medical and dental colleges.
Why was Central government-run medical institutions like JIPMER in Puducherry exempted from NEET and how are state-run establishments like Madras Medical College inferior to them, he asked.
He reiterated that entrance examination went against rural, poor and oppressed students.
The option to sit for NEET thrice would take away the "level playing field", thus reducing chances of poor and favouring students from well-off backgrounds, he claimed.
The DMK leader said only the rich could go for special coaching for such exams and not those from rural areas or belonging to oppressed sections.
He exhorted the general public to take part in the July 27 human chain protest across Tamil Nadu to oppose the Centre's "hegemony" of NEET.