"Of course it will have some adverse impact on inflation. But the oil prices are going up and petrol is a decontrolled item," he told reporters here.
Oil companies yesterday raised petrol prices by Rs 1.80 per litre, citing the impact of rupee depreciation on the cost of crude oil imports. Following the increase, petrol in Delhi will cost Rs 68.64 a litre.
On why the government's allies were not kept in the loop about the price hike, Mukherjee said, "Nobody in the government knows... because petrol prices are increased by the petroleum companies, not by the government. Diesel, kerosene and gas are controlled items."
UPA partner Trinamool Congress has expressed unhappiness over the petrol price hike.
While the CPI(M) has demanded the immediate roll-back of the petrol price hike, the main Opposition party, the BJP, has termed it as "midnight deceit".
The petrol price hike comes at a time when inflation is touching double digits and the move could have a cascading effect on prices.
Inflation in September stood at 9.72 per cent, much above the Reserve Bank's comfort level of 5-6 per cent.
Petrol prices were freed from government control in June last year.