Among the victims, nine are from Andhra Pradesh while the remaining are from Tamil Nadu, he said.
The compound wall was constructed by a private warehousing company and its owners -- Ramanathan and his brother Balu -- have been arrested, district Superintendent of Police Saravanan said.
A 19-year-old youth, Nagaraj, was rescued from the debris and has been admitted to hospital with minor injuries. Heavy rains had lashed the area last night.
Jayalalithaa condoled the deaths and announced an assistance of Rs. 2 lakh each for the next of the kin of the deceased and Rs. 50,000 to the injured.
She also instructed police officials to take stern action against those responsible for the tragedy.
The incident occurred eight days after an 11-storeyed building crashed at Porur, claiming 61 lives.
Meanwhile, Jayalalithaa announced formation of a Special Investigation Team headed by a Joint Commissioner of Police to probe the Porur building collapse.
The SIT comprises experts in engineering and architecture.
The government has already announced a commission headed by retired Justice R Raghupathy to probe the June 28 mishap. Police have registered a case and arrested six persons in connection with the tragedy.