"On her (Mayawati) proposal I will neither say yes nor no. The issue should be thoughtfully considered and discussed," Advani told reporters here before leaving for Uttarakhand.
"What her idea is behind the proposal, I will not speculate. New state formation cannot be done in haste," he said.
UP Chief Minister Mayawati has proposed division of the state into four states - Poorvanchal, Bundelkhand, Avadh Pradesh and Paschim Pradesh.
Advani noted that reorganisation of states was first done in 1954 on linguistic basis. Subsequently, Jharkhand, Uttarakhand and Chhattisgarh were carved out of Bihar, Uttar Pradesh and Madhya Pradesh.
"I felt it (demand for new states) was justified as the three states formed on linguistic basis had large areas," he said, adding that in the 1998 BJP manifesto they had made a commitment.
"We formed the three states when I was the Home Minister. We made the new states without any problem," he said, adding further division of UP should be done only after considering the issue threadbare.