* YPF is main jet fuel supplier in Argentina
* Gov't wants companies to boost investment in sector
* Companies previously accused of overcharging for diesel
BUENOS AIRES, Feb 21 (Reuters) - State-run Argentine airline Aerolineas Argentinas has accused three energy companies of overcharging for jet fuel, stepping up government pressure on leading supplier YPF, La Nacion newspaper reported on Tuesday.
Aerolineas filed a complaint with the country's antitrust commission earlier this month, accusing YPF, Royal Dutch Shell and Esso of selling the fuel at a price that is "far above the cost of production," La Nacion said.
YPF provides about 80 percent of the jet fuel used in Argentina, energy sector sources told the newspaper.
The country's center-left government has tightened the screws on the company, which is the local unit of Spain's Repsol , as part of a drive to get companies to increase investment in energy output.
Argentina's economy has grown at a sizzling pace in most of the last nine years, spurring demand for energy at a time when private investment in exploration and production has sagged. Costly energy imports have cut into the country's trade surplus.
After officials accused YPF and others of overcharging for diesel, the antitrust commission ordered changes in the way they set prices. And the government last week banned YPF from making foreign trade deals due to unpaid taxes.
A source at YPF said the company had not been informed of the complaint by Aerolineas Argentinas.
No one was available to comment at the country's antitrust commission or at Aerolineas Argentinas on Tuesday, a national holiday in Argentina.
Federal Planning Minister Julio De Vido, who oversees energy policy, responded to reports of fuel shortages at service stations by saying the government would ensure supplies if YPF did not.
"This is what we've always done, we had to import $9 billion in 2011 because the energy companies, and YPF in particular, did not produce enough to supply the domestic market," De Vido said in a statement published on the presidential website.
"They want to force us to let local prices follow international prices (higher), but we will not give in to this extortion," he said.
An industry source said that in recent weeks, YPF has had difficulty getting official authorization to buy the dollars it needs to import fuel. The government must pre-approve all purchases from abroad and related foreign currency deals.
De Vido did not refer to the issue of jet fuel. But President Cristina Fernandez, in her first speech after a three-week medical leave last month, slammed energy companies for charging global rates for the fuel.
"Nearly all the JP1 (jet fuel) is produced here, with the exception of a very small amount that is imported, which I think they do to justify charging us the international price," Fernandez said.
Esso was purchased last year by Pan American Energy, which is controlled by BP Plc .