Italian oil company Eni led the charge back into Libya on Monday as rebels hailing the end of Muammar Gadaffi's rule warned Russian and Chinese firms that they may lose out on lucrative oil contracts for failing to support the rebellion.

Gadaffi's fall will reopen the doors to Africa's largest oil reserves and give new players the chance to compete with established European and US oil majors.

'We don't have a problem with Western countries like Italian, French and UK companies. But we may have some political issues with Russia, China and Brazil,' Abdeljalil Mayouf, information manager at Libyan rebel oil firm Agoco, said.

The comment signals a potential setback for those countries which opposed tough sanctions on Gadaffi or pressed for more talks and would leave European and US companies to capture billions of dollars worth of oil exploration and construction contracts in the Opec member nation.

Shares in Eni, top producer in pre-war Libya, gained as much as seven per cent, as its chairman Giuseppe Recchi said Libyan oil and gas flows could restart before winter. Brent oil futures fell just over a dollar a barrel on the anticipated resumption of Libyan exports

Shares in Austria's OMV and France's Total also rose by 3-5pc and US oil firms with operations in Libya followed the trend.

Italy's Foreign Minister Franco Frattini said staff from Eni had arrived to look into a restart of oil facilities in the country's east.

'The facilities had been made by Italians, by Saipem, and therefore it is clear that Eni will play a No 1 role in the future,' Frattini said.-Reuters