"The contest in the three constituencies will be triangular among the ruling AIADMK, main Opposition DMK and BJP," senior BJP leader and Rajya Sabha MP L Ganesan told reporters at the airport.
Though PMK and DMDK too had named their candidates, the contest would be only among the three parties, he said.
The Election Commission had earlier this month announced that polls to Thanjavur and Aravakurichi Assembly seats, which it had rescinded in May in view of complaints of distribution of money, will be held on November 19.
Ganesan said he will be part of President Pranab Mukherjee led delegation to Nepal. Mukherjee will be paying a state visit to the Himalayan nation between November 2 and 4.
Authorities have taken all precautionary steps to tackle rains in Tamil Nadu during the present monsoon, he said.