* Mexico asks for IMF credit line boost
* Calderon says does not plan to use facility
* IMF chief sees uncertainties in world economy (Adds quote from Carstens)
By Patrick Rucker and Luis Rojas
MEXICO CITY, Dec 14 (Reuters) - The International Monetary Fund is set to boost its credit line to Mexico to more than $70 billion as a safety net for Latin America's No. 2 economy in case of more global financial market turmoil.
President Felipe Calderon said on Tuesday Mexico had asked the IMF to extend the country's current credit line from about $48 billion to about $72 billion over two years.
"This is a financial insurance policy that will fully protect the economy from any external turbulence," Calderon said after meeting with the IMF's managing director, Dominique Strauss-Kahn.
"This is a credit line of a precautionary nature that, just like in past instances, Mexico does not plan to use," Calderon added.
Strauss-Kahn said he planned to push ahead quickly to get IMF executive board approval for the request. He praised Mexico's economic policies during the global financial crisis and said the country was one of the IMF's "platinum members."
The extension, which he said would be worth about $73 billion, was a precaution that would help maintain external confidence in Mexico given the uncertain global environment, characterized by uneven growth.
"When you look at Europe you can see that things are not that good, especially because of the debt crisis," Strauss-Kahn said. "When you look at the U.S. it is unclear, so far, how (things) will be in 2011 and 2012. It is not bad, but not as good as expected. It will remain uncertain."
Central bank governor Agustin Carstens said slow economic growth in Europe and the United States were among the main risks to the outlook, along with protectionist pressures.
"A protectionist war, a war of monetary policy measures where you start to close markets ... a tariff war or a currency war between the U.S. or Europe or other countries like China, that would be very costly for world growth," he told local radio.
"It is a very uncertain, volatile world with very clear spots of danger in the euro zone, in the United States, in China that could eventually effect us," Carstens said.
Mexico has yet to tap its credit line with the IMF, which first set up the facility in early 2009 when the global financial crisis knocked the country's peso currency to a record low. Poland and Colombia have similar precautionary credit lines.
Mexico's currency commission, made up of the central bank and Finance Ministry, said the credit line, when added to the central bank's dollar reserves, would provide Mexico with close to $200 million to defend its currency from external shocks.
The IMF forecasts the Mexican economy will grow 5.0 percent this year and 3.9 percent in 2011, compared with expected global growth next year of 4.2 percent.
Mexico and other emerging market economies are concerned about what will happen when the United States and other rich nations eventually raise interest rates and rein in government spending.
Higher U.S. rates could lead investors to pull money out of emerging markets like Mexico to invest them in safe-haven U.S. Treasury debt. (Writing by Michael O'Boyle and Krista Hughes)