The JD(U) leader on Saturday reached the national capital to address the Adhikar Rally, where he will be the key speaker, at the Ramlila ground, party members said.
JD(U) president Sharad Yadav, who will also address the gathering, said in 2000 when Bihar was bifurcated, leading to the creation of Jharkhand, the state's mineral strength collapsed.
"The division of Bihar badly affected the state's financial strength. The (NDA) government had then assured a special package for Bihar but it did not see the light. So we are now seeking a special status for Bihar so that it can develop," he said.
The Adhikar rally is taking place days after Kumar welcomed Finance Minister P Chidambaram's budget speech announcing the government's intent to change the criteria of deciding the backwardness of states.
"We welcome the initiative made by Chidambaram. Prime Minister Manmohan Singh also talked about the growth story of Bihar. People in the central government, too, are feeling that there should be justice to Bihar," Yadav told PTI.
Kumar had on Friday said the finance minister's announcement has rekindled the hope of getting special status for his state to spur economic growth.