"Since he was found in indulging in anti-party acitivities causing disrepute to the party, R Nataraj has been dismissed from the party with effect from today", she said in a statement here.
Cadres are requested not to have any kind of contact with him in future, she said.
A 1975 batch IPS officer, Nataraj became City Police Commissioner in 2003. He had also served Tamil Nadu Public Services Commission as its Chairman.
Last year, he had formally joined AIADMK.