Oil production in Brazil has been disrupted by a strike against a planned auction for rights to explore a huge offshore oil-field near Rio de Janeiro. 42 platforms and several refineries have been affected. Union leaders say 90 per cent of employees of the state oil company, Petrobras joined the strike yesterday. They say the Libra oil-field auction will damage national interests by allowing foreign companies to share production rights with Petrobras. The 40,000 Petrobras employees are also demanding a pay rise. The Mines and Energy Minister Edison Lobao said that the auction will go ahead as planned on Monday despite the industrial action. The Libra field is a deep-water oil-field in the Santos basin some 230 kilometres off the coast of Rio de Janeiro. It belongs to the Brazilian National Petroleum Agency and is part of huge oil reserves discovered in 2010 under a layer of rock, sand and salt beneath the seabed.