(Adds finance minister quote, background on sale)
BOGOTA, Aug 12 (Reuters) - Colombia has postponed the sale of its majority stake in power generation utility Isagen for as long as a year, Finance Minister Mauricio Cardenas said on Tuesday.
The government hopes to raise about $3 billion from the sale of the company, which is Colombia's third-largest energy generator and operates six electricity generators, to spend on badly-needed infrastructure improvements across the nation.
Isagen had been scheduled for auction on Aug. 22.
Cardenas said the government has been in constant communication with interested companies from the United States, France, China and Spain. He added that several of them had asked for a delay in the deadline.
"For the nation, it's desirable to have various interested parties that will compete (in the auction), and we will be able to sell at the best value possible. For that reason we won't rush. What we need is competition so we won't do this under pressure," Cardenas told reporters in Bogota.
Isagen fell 14.8 percent to 2,745 pesos ($1.46) a share on Bogota's stock exchange following his comments.
Colombia's government will set a new deadline at a later date, Cardenas said, adding that the sale will occur within the next year. The government said it hopes to attract more interested companies to the auction.
The government has received interest in Isagen from U.S.-based Duke Energy, China Haudian Corporation, Generco and Spain's Gas Natural.
The sale process has dragged through several governments and was halted for two months until May for a review by a judicial authority after a pressure group tried to stop the privatization.
Isagen had 2,212 megawatts of mostly-hydroelectric installed capacity, or about 15 percent of national installed generation capacity, as of 2012, according to Colombia's Mines and Energy Ministry. (Reporting by Carlos Vargas; Writing by Peter Murphy; Editing by Helen Murphy and Paul Simao)