Argentina is likely to strike an agreement with the International Monetary Fund before the end of the month, Morgan Stanley's analysts said on Monday, adding that any move to dollarize the long-troubled economy would need substantial preparation.

"We keep thinking an agreement with the IMF is within reach, likely before the end of the month," Morgan Stanley's economists said in a note.

Argentina, which has a long history of debt defaults, is trying to revamp its $44 billion IMF loan programme, having seen finances damaged over the last year by a severe drought that has hammered its crops. The IMF staff's pending fifth review evaluates Argentina's performance between January and March.

The country will have a mandatory primary vote locally known as PASO on August 13 and general elections on October 22, which the conservative opposition is currently expected to win according to polls.

"Our focus remains on the negotiations between the authorities and the IMF, then the PASOs," Morgan Stanley said. "After that, a whole new ball game starts". (Reporting by Marc Jones, editing by Jorgelina do Rosario)