Akhir 27, 1432 / April 1, 2011, SPA -- Striking workers in central African oil exporter Gabon are shutting down the nation's oil fields to press for more local hiring in the sector, a union official said on Friday. Some 50 percent of the country's 220,000-240,000 barrels of daily crude oil output will be shut by the end of the day, with the rest scheduled to be halted within 48 hours, Guy-Roger Aurat Reteno, secretary general of the ONEP union said, according to Reuters. "Since midnight we started to shut down Gabon's oilfields. The shutdown procedures are ongoing," he told Reuters by telephone, adding distribution of fuel in the country was also paralysed. Gabon's oil sector is one of the continent's most mature and has been in steady decline since output peaked at around 370,000 barrels per day in 1997. Energy revenues contribute account for about 40 percent of the country's budget. The ONEP union represents about 4,000 of the country's 5,000 oil workers, and has a long history of grievances over pay and local hiring practices. Gabon's government late last year agreed to trade union demands to limit foreign workers in its oil sector to 10 percent and require all executive posts to be held by Gabonese -- a decision the government has since rowed back from amid concerns it could slash foreign investment. President Ali Bongo Odimba said this week he supported "gabonisation" of the oil sector, but said the effort must proceed carefully to ensure the industry remained competitive. ONEP, which says its strike will continue indefinitely, says more than 83 percent of management positions in the oil sector are held by foreigners. Major players in Gabon's oil sector include Total, Shell, and Tullow. Gabon, one of a handful of sub-Saharan African countries with a Eurobond, has sought to diversify its oil-dependent economy while also soliciting the interest of oil companies to broaden their exploration efforts to revive the declining sector.