To be successful, the deal would have to be "broadly accepted" by Argentina's holdouts, said Fitch's senior director Morgan C. Harting, without specifying what would be a satisfactory approval rate.

"I think it's clear to the government staff that this ongoing dispute with holdout creditors is a real drag and that this needs to be resolved at some point," Harting said during an emerging markets conference organized by Fitch in New York.

Investors have been speculating that Argentina might be close to launching another debt offer for holdouts, but so far the country's government has said it has no such a plan.

President Nestor Kirchner's recent decision to pay back all of Argentina's $9.9 billion debt with the International Monetary Fund made some of those creditors even angrier as they believed the government should give them priority.

"I had expected, if anything, that soon after the elections (the offer to holdouts) might become more of a priority," said Harting.

"The fact that Argentina has repaid the IMF makes it more uncertain because there was a general understanding that the IMF would put a certain sort of pressure to resolve the issue."

Fitch defines a "restricted default" rating as indicating an entity that has failed to make due payments on some but not all material financial obligations. It ranks just above "D" for default.