Chennai, Aug 13 - Campaigning by political parties for by-elections in five assembly constituencies in Tamil Nadu is in full swing.

By-polls are being held in Bargur, Thondamuthur, Cumbum, Illayangudi and Srivaikundam constituencies of the state assembly Aug 18 and the campaigning will end Aug 16.

The AIADMK, the PMK and the MDMK are boycotting the polls, so the fight is between the ruling DMK-Congress combine on one side and the DMDK, the Bharatiya Janata Party (BJP), the Communist Party of India (CPI) and the Communist Party of India-Marxist (CPI-M) on the other side.

The ruling DMK is contesting in Bargur, Illayankudi and Cumbum while its ally Congress has fielded its candidates for Thondamuthur and Srivaikundam seats.

Actor-turned-politician Vijaykant's DMDK is fighting on its own in all five seats and the BJP, which also fielded five candidates, had to suffer the humiliation of seeing its Cumbum candidate join the rival DMK.

The CPI-M will be contesting in Thondamathur and Cumbum constituencies and the CPI will test its strength in Srivaikundam and Bargur.

Completing his campaigning in Illayankudi, Srivaikundam and Cumbum, Vijaykant is canvassing for votes for his party in Bargur.

His wife Premalatha is campaigning at Srivaikundam and is expected to visit other constituencies as well.

For the DMK-Congress combine, the star campaigners are Deputy Chief Minister M.K. Stalin, and his sister and Rajya Sabha MP Kanimozhi apart from state and central ministers.

While Stalin will be campaigning at Thondamathur, Kanimozhi will be canvassing for votes in Srivaikundam Thursday.