EMERGING MARKETS-LatAm currencies firm after U.S. data

* Brazil's real under pressure on central bank plans

* Strong U.S. new home sales data boosts region

* Mexican peso firms 0.2 pct, Brazil's market split (Updates prices, adds comments)

By Samantha Pearson and Michael O'Boyle

SAO PAULO/MEXICO CITY, July 26 (Reuters) - Latin American currencies firmed on Monday after data showed U.S. sales of new homes surged in June, restoring some confidence in the recovery of the world's biggest economy.

But Brazil's currency markets were mixed due to expectations that the country's central bank may shift its involvement in the market.

Fears over a fresh slowdown in U.S. growth have hit Mexico particularly badly since the country sells about 80 percent of its exports to its northern neighbor.

But data on Monday showing that sales of new, single-family homes rebounded in June sent Mexico's peso to its strongest level in more than a week. For details, see [ID:nN26203473]

The Mexican currency MXN= firmed 0.24 percent to 12.700 per dollar.

"The sales data came in above what was expected and by a lot, so this is giving a little more certainty to the outlook," said Omar Martin del Campo, a trader at Banco Ve Por Mas in Mexico City.

The Chilean peso CLP= edged 0.17 percent stronger to 519.10 per dollar as the price of copper, the country's main export, touched a 10-week high. [ID:nLDE66P0SW]

But traders were cautious after the Chilean peso clocked its biggest weekly gain since May on Friday, due to the expectation of greater dollar inflows as the state moves to cash in its copper revenues.

According to the international reference rate, the Brazilian real BRL= was 0.34 percent stronger at 1.7675, buoyed by the strong U.S. economic data.

REVERSE SWAPS DIVIDE BRAZIL'S MARKET

But on the local spot market, the real BRBY was 0.57 percent weaker at 1.768 compared to Friday's closing level.

Traders attributed the difference to chatter about a possible shift in the way Brazil's central bank intervenes in the country's currency markets.

"Late last Friday the Central Bank of Brazil (BCB) 'checked' with FX dealer desks the demand for 'reverse swaps'," said Tony Volpon, Latin America strategist with Nomura Securities.

Reverse swaps are a form of derivative that would allow the central bank to take a long position in the U.S. dollar futures market in exchange for a short position in the interest rate markets.

Selling reverse swaps would be a way to reduce the arbitrage opportunities in the market, which have arisen due to the huge reserves the central bank has amassed through daily U.S. dollar auctions.

Brazil's central bank informally consulted the market around 1740 local time on Friday, according to one trader, causing the international reference rate to weaken sharply in late trading.

But by that point, the local spot market in Sao Paulo had already closed for the day. As such, Friday's closing level on the local spot market was much stronger than the international reference rate, meaning that Monday's currency moves were compared against widely different bases.

The last time the central bank offered reverse swaps was in September 2008.

"In fact it is a bit of a mystery why the BCB is not doing this already if its implicit goal is to depreciate or dampen the Brazilian real," Nomura's Volpon said.

However, Brazil's central bank has been reluctant to use derivatives as a tool for currency intervention because of their lack of transparency, wrote analysts at J.P.Morgan in a note earlier this month.

The real also pared gains after Brazil's current account deficit for June came in far worse than expected compared to the year-ago period. Imports jumped faster than exports and companies sent more money abroad. [ID:nN26154475]

"But the current account deterioration has been going on for some time now," said Flavia Cattan-Naslausky, a strategist at RBS Securities. The expectation that the central bank will resume reverse swaps was exerting a bigger pressure on the currency, she said.

(Additional reporting by Silvio Cascione in Sao Paulo and Jean Luis Arce in Mexico City; Editing by Diane Craft)

(samantha.pearson@thomsonreuters.com; Reuters Messaging: samantha.pearson.thomsonreuters.com@reuters.net; +5511-5644-7736)