The Central Bank said foreign reserves were now equal to 5.9 months of imports.
The central bank has been buying dollars heavily in the forex market as weak credit curtailed imports and the trade gap narrowed, amid a pick-up in exports.
In April, the government the government also sold a 500 million US dollars sovereign bond, the proceeds of which will generate imports in the future.
The Central Bank said there was a 'balance of payments surplus' of 1.544 billion US dollars in the first four months of the year, up from 352 million US dollars a year earlier.
The Central Bank had bought 550 million US dollars from forex markets to prevent the rupee from appreciating and to build up reserves.