NEW DELHI, June 17: No, it's not the cigarette major ITC, but the public sector oil major ONGC which has the largest amount of disputed tax liabilities. While ITC continues to battle out its case for its Rs 876.2 crore excise liability, ONGC's total disputed tax liability adds up to a whopping Rs 2,157 crore. While the disputed corporate tax liability is Rs 1,417.4 crore, the disputed excise liability is Rs 739.5 crore.Among the public sector, the largest tax disputes pertain to the oil sector, with Indian Oil Corporation's dispute adding up to Rs 339 crore, BHEL's is Rs 307 crore, Cochin Refineries' is Rs 161 crore, Mangalore Refinery Rs 148 crore and BPCL Rs 108 crore. Punjab National Bank has a corporate tax dispute of Rs 485 crore, according to the latest review of the Centre for Monitoring Indian Economy (CMIE).The amount stuck in corporate tax disputes for around 1,140 firms is a whopping Rs 6,270 crore of which Rs 4,260 crore pertains to the top 25 firms. For excise duties, the disputed amountis Rs 5,851 crore, and Rs 3,895 crore pertains to the top 25 firms. If all firms go in for the Kar Vivad Samadhan scheme, the Government would mop up Rs 5,000 crore, or more (Rs 2,900 crore from excise duty), says CMIE.