Wintershall, the oil and gas unit of German chemicals group BASF, has boosted output in Libya to three times what it was in the fall, but ageing pipeline infrastructure is limiting its production capacity, its chief executive said.

The second-largest foreign oil firm in Libya before the civil war, Wintershall used to produce some 100,000 barrels per day (bpd) before Muammar Gadaffi was removed from power last year.

With more than $2 billion in investments and 150 wells sunk in Libya, the company was second only to Italy's Eni among foreign firms before the conflict.

"We started with a production of 20,000 bpd in October and we have now stabilised to an average of 60,000 bpd," Rainer Seele said on the sidelines of an energy conference.

Wintershall could produce 90,000 bpd from its fields but Libya's old pipeline system is preventing the company from transporting the crude from the desert to the coast in the quantities it would want to.