* Brazil's central bank chief says GDP may surprise upwards * MSCI's Latam stocks index set for best day since December * Mexico's president presents constitutional reforms * Latam currencies up 1%, stocks jump 2.5% (Updated at 3 p.m. EST/2000 GMT) By Amruta Khandekar and Lisa Pauline Mattackal Feb 6 (Reuters) - Most Latin American stocks and currencies climbed on Tuesday as China's efforts to ramp up support for its downtrodden markets boosted risk appetite and lifted commodity prices, though caution about the timing of U.S. interest rate cuts kept a lid on gains. MSCI's index for Latin American currencies rose 0.9% while regional stocks jumped 2.5%, posting their best day since Dec. 14 and in line with broader emerging market peers. A slew of announcements from China's securities regulator, signaled more support for the country's battered stock markets, boosting commodity prices and lifting global emerging market assets. "Risk on as the China national team supports equities and hope for further stimulus continues ahead of Lunar New Year," Bob Savage, head of markets strategy and insights at BNY Mellon, wrote in a note. Savage, however, noted that "most doubt this is sustainable, as buying rather than selling requires confidence both at home and abroad." Brazil's Bovespa index led the charge among Latin American indexes, gaining 2% on back of financial stocks. Shares of Bradesco, a financial services company, leapt more than 5%. Brazilian payment processor Cielo said late on Monday that Bradesco and Banco do Brasil had decided together with Grupo Elopar to launch a tender offer to take Cielo private. Itau Unibanco rose 3.7% after its CEO said the company may pay out extraordinary dividends for 2024. Both stocks and foreign exchange indexes in Latin America have risen after two straight days of declines as traders dialed back expectations of rate cuts by the Federal Reserve in March. The Brazilian real rose 0.4% after the governor of the central bank, Roberto Campos Neto, said an upward surprise in economic activity is anticipated. The central bank said earlier on Tuesday in the minutes of its latest policy decision that a tighter labor market, with above-inflation wage rises, could slow the decline of inflation to the central bank's target. "The forward guidance (unchanged) signals the maintenance of the current pace of rate cuts in the next meetings and the need to maintain a contractionary monetary stance," Goldman Sachs economists said in a note. China's support measures lifted prices of copper, helping Chile's peso bounce off more than a one-year low. The currency was last up 0.7%. Chile is the world's leading copper producer. The Mexican peso advanced 0.4% as oil prices rose, while Mexican stocks rose 1.3%. Mexico's President Andres Manuel Lopez Obrador proposed sweeping constitutional reforms on Monday, including measures to overhaul the judiciary, electoral law, pensions and environmental regulations just months before Mexicans will vote to choose his successor. Argentinian stocks fell 3% as investors awaited the outcome of voting on parts of libertarian President Javier Milei's economic reform bill. Key Latin American stock indexes and currencies at 2000 GMT: Latest Daily % change MSCI Emerging Markets 1000.03 1.7 MSCI LatAm 2586.90 2.52 Brazil Bovespa 130248.90 2.08 Mexico IPC 58994.46 1.32 Chile IPSA 6002.50 -0.05 Argentina MerVal 1219096.97 -3.323 Colombia COLCAP 1274.24 0.14 Currencies Latest Daily % change Brazil real 4.9625 -0.02 Mexico peso 17.0495 0.36 Chile peso 946.4 0.74 Colombia peso 3956.11 -0.13 Peru sol 3.8498 0.03 Argentina peso 829.5000 -0.05 (interbank) Argentina peso 1125 3.11 (parallel) (Reporting by Amruta Khandekar; Editing by Andrea Ricci and Paul Simao)