(Adds NOC statement)
TRIPOLI, Sept 20 (Reuters) - Libyan state oil firm NOC has reopened the airfield at the southwestern Wafa oilfield after state guards ended a blockade, it said.
"NOC is thankful that those blockading the site stood-down following the corporation's public warning regarding this activity," it said in a statement.
NOC said output at the field had not been affected. Wafa produces around 40,000 barrels a day of crude and condensates as well as 400 million cubic feet of natural gas.
A field worker said a first flight would arrive on Saturday.
The runway is used by the company to transport workers and equipment as it is too dangerous to travel by road in the chaotic country that is still trying to establish the rule of law since veteran leader Muammar Gaddafi was ousted in 2011.
NOC had said in a statement earlier on Thursday that the protesters were planning to "extort" Mellitah, the joint-venture between ENI and NOC that runs Wafa and other operations, for a "corrupt" contract, without giving details.
Guards, paid by the state to protect oil faculties, as well as other groups regularly seize oilfields to pressure weak authorities into giving them extra pay and benefits, part of the chaos in the OPEC producer since 2011.
NOC and other government entities have agreed in the past to some demands in the end to keep oil and gas exports flowing, Libya's only source of income. (Reporting by Maher Chmaytelli, Ahmed Elumami, Ayman al-Warfalli, Omar Fahmy and Ulf Laessing; Writing by Ulf Laessing; Editing by Alison Williams)