Federal Reserve Chairman Ben S. Bernanke’s latest round of bond buying will reach $1.14 trillion before he ends the program in the first quarter of 2014, according to median estimates in a Bloomberg survey of economists.

Bernanke will push on with purchases of $40 billion a month of mortgage bonds and $45 billion a month of Treasuries, according to the survey of 44 economists, even as some Fed officials warn his unprecedented balance-sheet expansion will impair efforts to tighten policy when necessary.