LIMA - The consortium that operates Peru's massive natural gas field at Camisea is expected to launch an auction in October to sell fuel to the local market, the country's vice minister of energy said on Friday.

The group, which is made up of Argentina's Pluspetrol, Spain's Repsol, U.S.-based Hunt Oil and South Korea's SK Energy , runs lots 88 and 56 in the Andean region of Cuzco.

Critics have put pressure on President Alan Garcia to guarantee domestic gas supplies, saying export of the fuel could lead to shortages.

We know they (the Camisea consortium) should open the auction in October, and could award (lots) the following month, Camac said in a statement.

An official at Pluspetrol, which heads the consortium, said it's planning an auction, but declined to say when the sale might be and would not comment on the volumes that could be included.

Camac said fuel output from lots 88 and 57, which is controlled by Repsol and is thought to have around 2 trillion cubic feet of gas, would be part of the October auction.

In August, Repsol and the government agreed that production from the company's lot 57 would be sold exclusively to the domestic market.

The consortium says it has some 14.1 tcf of proven gas reserves that would last through 2047, though a recent study by an energy consulting firm estimated a more modest 8.79 tcf. (Reporting by Teresa Cespedes; Writing by Dana Ford; Editing by Fiona Ortiz)