The strike was called after the unions and Transport Minister MR Vijayabaskar failed to reach a settlement despite several rounds of talks over pending salaries and settlement of benefits to retired staff.
Members of trade unions affiliated to the ruling AIADMK, however, operated some bus services.
A senior official from the Transport department said private buses were also engaged to fulfil the passenger demand. He said the authorities had decided to engage private bus drivers and conductors to operate government buses.
Authorities have beefed up the security in Chennai and deployed more than 20,000 police personnel around bus depots. The police have said they will take stringent action against those disrupting operational bus services.