Chief Minister O Panneerselvam said that the government had already filed an interlocutory application in the Supreme Court to "stop Karnataka's illegal move" of building the reservoir.
"This government will take all efforts, including legal measures, to thwart any attempt made by the Government of Karnataka to construct a reservoir across Cauvery near Mekedatu," he said in the budget for the year 2015-16 presented before the Tamil Nadu Assembly.
Farmers in the Cauvery delta region in the state are up in arms against Karnataka's decision to construct a check dam at Mekedatu, insisting that it will affect the water flow to the lower riparian state.
The state government had already taken up the matter with the Centre.