The youth, in his early 20s, was handed over to Kotwali Police by AAP volunteers.
"He winked at me. He was looking at me in an inappropriate way. He also approached me near town hall, after which I slapped him. Following this, he started running. AAP volunteers who were there with me, chased him and handed him over to Kotwali Police.
"He claimed he was mentally unstable but even by evening his family could not produce any satisfactory evidence that he was undergoing medical treatment," Lamba, who is Delhi Government's Parliamentary Secretary for Tourism, said adding that she had asked the police to take necessary action.
"Is manchale ko bhi nahi pata chala ki main kaun hoon, pehale muskuraya, phir aankh maari, phir kandha, phir mera kas kar chata, ab jail.." she tweeted.
Meanwhile, police said the accused was identified as Rajesh, a resident of Baljeet Nagar area.
"A written complaint has been made to us in this regard and we are looking into the matter," a police officer said.