* Tax on foreign borrowing not seen hurting real
* Brazil real firms 0.24 pct, Mexico peso flat
By Silvio Cascione and Michael O'Boyle
SAO PAULO/MEXICO CITY, March 29 (Reuters) - Brazil's real on Tuesday shrugged off the government's latest effort to curb financial flows that have inflated the currency's value, although authorities could step up efforts.
Brazil's government on Tuesday raised a tax on foreign borrowing for loans of up to 360 days. But the move had been widely expected by financial markets. Some had feared the government could take more drastic measures.
"This measure will not make any difference," said Flavio Serrano, senior economist at Espirito Santo Investment Bank.
The real firmed 0.24 percent to 1.656 per dollar on the local spot market.
The country's finance minister called a press conference for after 1530 GMT.
Financial flows into Brazil have been tempted by the huge spread between interest rates in developed markets and Brazil's double-digit rates.
In October, Brazil tripled to 6 percent the so-called IOF tax it charges foreigners when they buy local bonds.
But analysts said the lack of a tax on locals was allowing domestic banks and companies to borrow abroad, invest in Brazil's high-yielding debt and pocket the difference between interest rates.
Analysts said market players would likely find ways around any new measures, short of a broad flat tax on all inflows.
"We are skeptical that this new measure will change the trend of (the real's) appreciation," Barclays Capital wrote in a note to clients.
Barclays noted much of current and future inflows would likely be related to equity investments, which are only taxed at a rate of 2 percent.
The real has firmed about 5 percent from a November low despite increased government and central bank efforts. However, analysts said the government could try more measures if the real firms back past 1.65 per dollar.
Mexico's peso traded flat around 11.9750 per dollar. The cost of dollars in pesos could not push through support at 11.95 per dollar, and pulled back after weak data in the United States, Mexico's top trade partner.
Data showed U.S. consumer confidence fell in March as households worried about inflation, while home prices fell for the seventh straight month in January, pointing to a loss in momentum in the economy.
Mexico's peso hit its strongest in nearly 2-1/2 years this month on signs of recovery in the United States, which buys most of Mexico's exports.
Chile's peso bid 0.33 percent weaker to 481.90 per dollar, hurt by a fall in the price of copper, the country's main export.
Peru's sol edged back after it slumped by the most in nearly two years in the previous session following polls that showed a left-wing nationalist presidential candidate leading the race.
The sol firmed a slight 0.07 percent to 2.811 per dollar as it edged back from its weakest close since December in the prior session. (Editing by Jan Paschal)