"Why should you have any Lokpal? If an agency is created which will not stop corruption, will lead to increased corruption and provide protection to ministers, then what is the point," he told reporters here.
"We were not interested in just the word Lokpal. You can name it anything. The government has not done a favour to the people of the country (by the bill). It is the government's constitutional duty to give a corruption-free regime," he said.
"Some people are saying they are happy that a beginning has been made, but has the government done us a favour?" asked Kejriwal, saying the people of the country were suffering due to corruption and price rise.
He sought to know why cannot the United Progressive Alliance (UPA) government come out with changes in the law to make it stronger now.
"Why can't the changes and amendments be made now? This means that the government thinks if a strict law is passed, all of them will go to jail," he said.
"Half of the ministers of the same cabinet, which passed the bill today, will be in jail if a strong Lokpal comes," alleged Kejriwal.
The union cabinet Thursday approved amendments to the Lokpal Bill suggested by a select committee of the Rajya Sabha.
The bill, passed by the Lok Sabha, is pending in the Rajya Sabha, and was referred to a select committee of the upper house, which suggested several amendments to the legislation.
The bill will now be put to vote in the upper house.