"The Finance Minister Pranab Mukherjee is very flexible to accommodate view of the state governments," Modi, who is also Deputy Chief Minister of Bihar, told reporters.
A key concern of states is the autonomy to levy taxes. The states also have problems with the dispute regulation panel.
Modi indicated that the central government was willing to consider the states demand on the issue of compensation for reduction in central sales tax.
"You require flexibility, and now I am finding that there is a flexibility in the attitude of the Finance Minister and in the State Council," he said.
Modi's statement assumes significance as the Bharatiya Janata Party (BJP) ruled states have so far been opposing the new tax regime.