The protesters alleged that the Central government and RBI were denying currency to keralites.
The activists, led by their president Mujib Rehaman, came in a procession and squatted in front of RBI raising slogans.
NCP President Uzhavoor Vijayan inaugurated the agitation.
NCP is a coalition partner of the ruling CPI(M) led LDF in Kerala.
Kerala had witnessed acute shortage of currency notes early this month with government finding it difficult to disburse salaries and pension through state treasuries.
RBI had informed that the shortage was due to the truckers strike.