Left parties on Monday opposed any increase in petrol and diesel prices in step with the hike in global oil prices and higher taxes, and asked the government to restructure duties to protect the consumers.The leaders of the Left parties had a hour-long meeting with Finance Minister P. Chidambaram and Petroleum Minister Mani Shankar Aiyar to demand a rollback of excise duty increase announced in the Budget this year, shelving the proposal to raise road cess and creation of price stabilisation fund out of the cess collected on domestic crude oil.While the petroleum minister has been pressing for a revision in the petrol and diesel prices to ensure that the oil marketing companies do not loose out money due to underrecoveries, the Finance Minister had also conveyed earlier that he was not much in favour of further restructuring of duties on petro products.Petrol prices need to be raised by Rs 4.59 a litre, half of it (Rs 2.52) on account of increase in excise duty. Similarly, diesel prices need to be hiked by Rs 4.97 per litre, including Rs 1.53 due to excise effect. The required increase also includes Rs 0.61 per litre each due to increase in road cess.Talking to reporters after the meeting, Communist Party of India (CPI) Leader D. Raja said, ‘‘we have asked the government not to increase prices but consider other ways (of containing the impact of global spike).’’ Dipankar Mukherjee said the Finance Minister’s statement while presenting the Budget that the duty changes were revenue neutral and would not result in any increase in retail price, was ‘false’. ‘‘It is felt the proposed changes in duty structure have actually helped the standalone private refineries,’’ he added.‘‘Import duty reduction has helped the refining sector, but the excise duty changes, applicable after refining, affect adversely the marketing/retail sector managed by the oil PSUs,’’ Mukherjee said.