The laborers spotted three idols at a depth of about eight feet when they were digging on the land in Thiruvilaiyattam village and alerted revenue officials.
The idols of Perumal, Sridevi and Boodevi were intricately carved and might be ancient, Tarangambadi Tahsildar Ganapathy said.
The Perumal idol is 85 cm high while the other two idols are of same size - 67 cm high.
Other details about the idols, including antiquity value, would be known only after detailed archaeological examination, the tahsildar said.
Local people said a Perumal temple existed at the spot 800 years ago. The shrine over the years got buried underground and the idols must be at least 800 years old, they said.