By Christine Murray

MEXICO CITY (Reuters) - Mexican billionaire Carlos Slim said on Thursday that if President-elect Donald Trump succeeds in office, it will be good news for Mexico, and that he would be more worried as an American than a Mexican about the next U.S. government.

Slim, a telecoms tycoon who spent several years as the world's richest man, says he has never met Trump, but the two businessmen traded barbs during a bruising U.S. election campaign in which Trump vowed to build a wall along the southern border to keep out Mexican immigrants.

In October, Trump accused Slim, the top shareholder in The New York Times Co, of trying to help Democratic Party candidate Hillary Clinton, even though Slim's shares have limited voting rights.

Then, a few days before the Nov. 8 election, Slim said Trump's plans could "destroy" the United States economy.

In his first public comments since Republican Trump's stunning victory, Slim said that Trump's plans could risk the international leadership role the United States plays.

"I'd be more worried if I were American," he said in an interview with Bloomberg Television. "If he's going to close the economy ... if he's going out of the NATO and other international (bodies)."

But Slim added that Trump's potential success would also be Mexico's, arguing that a 4 percent U.S. growth rate and the creation of millions of jobs would benefit Latin America's second biggest economy.

"That's fantastic for Mexico," Slim said at a Bloomberg event in Mexico City.

Mexico should turn its attention inward and invest to spur growth, Slim said. He said Trump's win had not affected any of his own investment plans.

Still, Slim also warned the audience about the effects of some of the protectionist measures Trump has threatened to impose, including steep tariffs on Mexican-made goods.

"To put a tax of 35 percent on our exports will be paid by (U.S.) consumers," he said while speaking on a panel alongside Bloomberg founder and former New York City mayor Michael Bloomberg.

Trump has said he would renegotiate or scrap a trade deal with Mexico. Trump attacked U.S. companies investing south of the border, battering Mexico's peso.

"It's not easy to build a wall, anyway they build tunnels and most people arrive by plane," Slim joked in comments before the election, referring to drug cartels digging tunnels to smuggle their products into the United States.

(Reporting by Christine Murray, additional reporting by Enrique Andres Pretel; Writing by Gabriel Stargardter and Dave Graham; Editing by Chris Reese and Grant McCool)