Construction work was going on in Upper Coonoor area, where the man, Ravikumar (42) and some others were involved in deep digging, police said.
Suddenly, the loose soil caved in and Ravikumar and another person were trapped.
Ravikumar was pulled out after some time, but found dead, police said while the other worker came out safely.
A search was on to ascertain whether any other worker was caught in the soil, they said.
Ravikumar was a functionary of Viduthalai Chiruthaigal Katchi in Melur in Madurai district.