Nigeria's state oil company on Friday urged motorists not to engage in panic petrol buying, a day after a trade union representing oil workers began a strike that raised fears of future fuel shortages. Petrol shortages caused lengthy queues for motorists seeking to fill their tanks earlier this year after fuel importers struggled to find dollars needed to pay for refined oil products due to foreign exchange restrictions imposed by the central bank.The Petroleum and Natural Gas Senior Staff Association of Nigeria (PENGASSAN) on Thursday said 10,000 of its members, which include refinery workers and office staff, had begun industrial action over issues "critical to the survival" of the country's energy sector.There was no sign yet of any panic buying but the Nigerian National Petroleum Corporation (NNPC) cautioned members of the public against any form of panic purchase."The corporation has in stock enough products to satisfy local consumption requirements for the next 45 days," said NNPC spokesman Garba Deen Muhammad.Muhammad also said the state oil company had begun talks with trade union leaders to address their concerns.PENGASSAN said it decided to strike over issues such as joint venture funding and cash call arrears, which it said had stalled the creation of new jobs and investment in the sector.Cash calls are the government's financial obligations to joint venture projects between NNPC and international and local oil companies. ..