Colin Ellis, the firm's chief European credit officer, said the immediate focus was on whether the Greek parliament approved the proposed deal on Wednesday, and on whether financing could be found to meet a 3.5 billion euro payment to the European Central Bank next Monday.

"Rating upgrades are not likely over the near term given the downside risks," Ellis said, pointing out that it had taken around 18 months to raise Cyprus's rating after its bailout deal.

"The balance of risk is still heavily skewed in one direction."

Greece is currently rated Caa3 by Moody's after a downgrade at the start of the month. Unlike the other big rating firms, Moody's reflects in its ratings how much is likely to be recovered in a default, not only the binary issue of whether it is a default or not.Earlier, Standard and Poor's said it could upgrade Greece "pretty quickly" if the bailout plan looked like holding, although an exit from the euro currency union remained its longer-term expectation for the moment.

(Reporting by Marc Jones; Editing by Kevin Liffey)

By Marc Jones