(Adds economist’s comment, details) BRASILIA, April 28 (Reuters) - Brazil’s government increased its emergency cash buffer in March to cover future debt obligations and other due payments to more than 1 trillion reais, Treasury figures showed on Wednesday, as public debt also rose to a new all-time high. The Treasury swelled its liquidity cushion, essentially an emergency cash buffer, by 20% in nominal terms from the previous month to a new high of 1.12 trillion reais ($207 billion), it said in a monthly report. The amount is enough to cover more than seven months of debt maturities, the Treasury said, adding that some 435 billion reais of debt was scheduled to mature in April and May alone. Sergi Lanau, deputy chief economist at the Institute of International Finance in Washington, said having ample cash reserves to cope with shocks makes sense, especially in a country where fiscal vulnerability is high. “Since borrowing costs are likely to rise in Brazil and elsewhere, the treasury may be taking advantage of current rates to build buffers,” Lanau said. Brazil’s central bank raised interest rates in March for the first time in six years and is widely expected to do so again next week and in the coming months, as it tries to get inflation back down to target. Brazil’s federal public debt rose 0.85% in March from the month before to a new record high 5.24 trillion reais ($972 billion), the Treasury said, adding the total domestic debt stock rose 0.7% to 4.99 trillion reais. The average cost of servicing the public debt stock fell to a new low of 7.6% from 8.1%, largely due to a steep fall in the cost of servicing hard currency debt, Treasury said. The share of public debt in the hands of foreign investors rose again, edging up to 9.5% from 9.4% in February and 9.2% at the end of last year. That is still half of what it was in 2015, however.