"Prices of petrol and diesel would continue to go up and down and their rate varies every day," Kumar told reporters on the sidelines of the weekly 'Lok Samvad' (interaction with the public) programme.
Talking to reporters separately, Deputy Chief Minister Sushil Kumar Modi, who held the first meeting of the Group of Ministers (GoM) on the GST at Bengaluru last week, said petrol and diesel have already been in principle a part of the GST.
"Petrol and diesel are already part of the GST regime in principle and hence, there is no need to carry any amendment in the GST legislation. The issue is when to start the implementation of the GST on petrol or diesel, which needs a wider discussion in the GST Council," he said.
Sushil Modi heads a five-member GoM committee constituted by the Centre recently to look into technical challenges being faced by the GST registration and tax filing portal.
Asked if the inclusion of petrol and diesel in the GST would lead to lowering of their prices, Sushil Modi said he cannot make a categorical comment on the issue.
He said registration of house and other properties is also a part of the GST, though it has not been implemented so far.