Dhinakaran said his MLAs will approach the court against the disqualification even as the rebels dubbed the move as a "murder of democracy".
"Our MLAs will move the court and we will get justice," he told reporters at Kancheepuram district.
The action against the 18 MLAs, who had revolted against Palaniswami last month, was taken under anti-defection and disqualification rules of 1986, said a statement from Assembly Secretary K Bhoopathy.
It said the rules were in accordance with the Tenth Schedule of the Constitution.
"With the Honourable Speaker ordering for the disqualification of MLAs from September 18, 2017, they have lost their membership," of the House, the statement said.
MLAs who have been disqualified are Thangatamilselvan, R Murugan, Mariappan Kennedy, K Kathirkamu, C Jayanthi Padmanabhan, P Palaniappan, V Senthil Balaji, S Muthiah, P Vetrivel, NG Parthiban, M Kothandapani, TA Elumalai, M Rengasamy, R Thangadurai, R Balasubramani, SG Subramanian, R Sundarraj and K Uma Maheswari.
Decrying the Speaker's move, Vetrivel said, "This is the height of mistakes being committed by those in power," in an apparent reference to Palaniswami.
"This is the height of mistakes being committed by those in power...It is not easy to disqualify even one MLA...This is murder of democracy," he said in response to the disqualification of the 18 MLAs including himself.
He said it was for the court to decide whether or not the disqualification is valid.
"According to us, it is not valid," he added.
To a question, he declined to spell out his faction's next course of action, saying "not everything can be revealed now."
He, however, said, "let the floor test happen."
The action was taken to ensure the government's survival in a possible floor test since Palaniswami did not have the required 117 MLAs' support in the 234-member House, he claimed.
Dhinakaran loyalist and Perambur MLA, P Vetrivel, said they will move the court "as soon as possible" against Dhanapal's decision.
The 18 MLAs, who were disqualified today besides another, had on August 22 met the Tamil Nadu Governor Ch Vidyasagar and conveyed that they had lost confidence in Palaniswami.
One of the dissident MLAs, STK Jakkaiyan, had later switched camps to support Palaniswami.
These MLAs had since been demanding the removal of Chief Minister and have been hopping from resort to resort in Puducherry and Coorg apparently not to be persuaded to join the Palaniswami camp.
Their August 22 meeting with Rao had come a day after the formal merger of the two factions led by Palaniswami and then rebel leader and now Deputy Chief Minister O Panneerselvam.
Earlier, Chief Government Whip S Rajendran had urged the Speaker to disqualify the said MLAs for "anti-party activities" following their revolt against the Chief Minister.
Though the Speaker had issued notices to all the dissident MLAs seeking their individual presence, they had, however, not turned up. But Jakkaiyan had met the Speaker and given an explanation.
A resolution adopted at a meeting chaired by Palaniswami on August 28 had said Dhinakaran was "removed" from the post of Deputy General Secretary.
Opposition parties have since been insisting the Governor direct a floor test for the Palaniswami government for proving its majority in the Assembly.
In the 234-member House, AIADMK has a strength of 134 MLAs.
The RK Nagar seat fell vacant last year following the death of then Chief Minister J Jayalalithaa.
The Opposition has a strength of 98 including DMK's 89. Congress 8 and IUML one.
(Only the headline and picture of this report may have been reworked by the Business Standard staff; the rest of the content is auto-generated from a syndicated feed.)