"If these blockages continue it will have a big negative impact," Fanas told reporters, putting the losses at 6.43 billion dollars (almost 8 billion Libyan dinars) since the summer.
The protests have reduced Libya's crude oil exports to a trickle, he said.
"There are now very intense efforts so this problem will perhaps be solved."
Tribes, armed militia and members of the Berber minority have seized most oil ports and fields since August to demand more rights or pay rises.
Two years after the fall of late strongman Muammar Gaddaf, Libya remains in turmoil. Its economy is expected to shrink by 5.1 percent this year, the International Monetary Fund said this week.
Crude output has falled to 90,000 barrels per day from 1.6 million under Gaddafi.haos in Libya two years after the fall of Muammar Gaddafi.
Crude oil and gas are the country's main natural resources.