The four assembly seats where by-polls are to be held are: Aravakuruchi, Sulur, Thiruparankundram and Ottapidaram.
Voters in these four constituencies will decide the electoral fate of 137 candidates in the fray.
However, the main contest will be between the ruling AIADMK, principle opposition party DMK, and an Independent legislator-floated AMMK party.
By-elections for 18 Assembly constituencies were held on April 18 along with the Lok Sabha polls in the state.
According to Election Commission about 16,000 police personnel will be deployed in the four assembly seats for security purposes.
The results of the by-polls for 22 assembly constituencies are crucial for ruling AIADMK, opposition DMK and AMMK parties.
According to analysts, the AIADMK may not find it difficult to win eight seats out of the 22 to continue in power.
To attain a simple majority, the AIADMK has to win just five seats in the by-elections. In order to be safe against switching of camps by some of the lawmakers, the AIADMK has to win seven or eight seats.
However, the Supreme Court has stayed the disqualification proceedings against the three lawmakers.
DMK President M.K. Stalin said that along with the change in the Central government after May 23 - the day on which the Lok Sabha and by-election results will also be declared -- there will be a change of government in Tamil Nadu.
One interesting factor in this situation will be the election result for the Kanyakumari Lok Sabha seat. The Congress party's H. Vasanthakumar, representing the Nanguneri Assembly constituency, is contesting in the Lok Sabha polls from Kanyakumari constituency.
It will be interesting to see whether he would retain the Assembly membership or opt for Lok Sabha membership if he wins in the Lok Sabha polls.
"It will be an acid test for Stalin's leadership. Assuming Dhinakaran's AMMK wins some seats, what action Stalin will take will have to be seen," political analyst Raveendhran Dhuraiswamy had told IANS earlier.
It has to be seen whether the AMMK will join hands with the DMK combine to topple the AIADMK government.
"If the BJP retains power at the Centre and the political situation in Tamil Nadu turns fluid, then the former can suspend the Assembly for some time to stall the DMK," political commentator Maalan Narayanan told IANS.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)