Libya\'s oil industry will need at least $25 billion (Dh91.8 billion) in investment to increase its oil production to two million barrels a day, said the chairman of drilling-rig operator Challenger Ltd. \"Fields need to be developed, others redeveloped,\" Hassan Tatanaki said in a telephone interview on Friday. \"The Libyan oil industry needs a lot of revamping. We have to reinvest to be able to get the proper cost effective amount into the industry in terms of the country\'s production level.\" The armed conflict in Libya, holder of Africa\'s largest proven reserves, has reduced the nation\'s output to 100,000 barrels a day in July from the 1.6 million barrels pumped before the uprising started in February. A full recovery of production may take as long as three years, according to analysts\' estimates. Tatanaki, 53, said he intends to play a role in rebuilding Libya\'s oil industry, of which Challenger\'s 35 rigs across the country \"are the core\". His Libya Al Hurra charity, set up shortly after the unrest began, has been providing humanitarian aid and relief to refugees and those displaced by the conflict in Libya operating out of Egypt, Tunisia, Libya and the US. \"We\'re not just concentrating on just medical and food supplies,\" Tatanaki said. \"We also want to play a part in other ways so that in the next year or so we have a proper constitution, transparency that helps create a democracy.\" Forces loyal to Muammar Gaddafi continued to battle revolutionaries in the Libyan capital Tripoli, as the opposition National Transitional Council said the North African nation\'s humanitarian aid needs are \"urgent\". Rebel leaders worked to retrieve assets frozen by the United Nations and individual countries in an effort to obtain funding for food, and humanitarian and medical needs, transitional council Chairman Mustafa Abdul Jalil said at a press conference in Benghazi on Friday. Since fighting began in Libya, the number of people killed has \"exceeded 20,000\", Abdul Jalil said. Refinery to restart A refinery official says a major rebel-held refinery near Tripoli shut down since Libya\'s rebellion flared will soon start up again, which should ease fuel shortages that have sent prices spiralling. Mohammad Aziz, a long-time operations manager at the Zawiya refinery, says, \"After tomorrow, it will be operational.\" He says the refinery will start processing stored crude first, and hopes to begin receiving new supplies from the south in two days. Anti-regime revolutionaries control much of Tripoli and have secured the road from the capital to Zawiya on Libya\'s coast. In Tripoli in recent days, the cost of a 20-litre can of petrol has leapt to about 120 dinars (Dh360), some 28 times the price before fighting broke out months ago.