Registering a complaint on violation of the Model Code of Conduct, Congress spokesperson Nikunj Balar said: "This was a clear breach of the MCC by the Prime Minister.
"After coming out of the polling booth at Ranip, the Prime Minister stood on the steps of the vehicle in which he was travelling and was waving to the crowd on the road. He continued to do so for 10 to 15 minutes.
"Our Legal Cell Chairman Yogesh Ravani registered the complaint with Gujarat's Chief Electoral Officer B.B. Swain and to the Chief Election Commissioner Achal Kumar Joti in Delhi."
Mr Swain, however, said: "I don't have any such information till now about this, but I will check and tell."
Senior Congress leader and former Finance Minister P. Chidambaram tweeted: "Allowing a roadshow of PM on voting day is a gross violation of code of conduct. It is an election campaign. What is the EC doing?
"The images on TV will leave no one in doubt that the BJP and PM have conducted a full fledged campaign on polling day. Shocking violation of rules. EC is sleeping on the job.
"Let the media look at the images on the TV screens, search its conscience and reach a conclusion. There has not been a more blatant violation of the code of conduct on polling day."
PM Modi, registered as a voter in Ranip area of Ahmedabad, exercised his right at the polling booth at Nishan Vidyalaya in Ranip region of the city.