LONDON- Ratings firm Moody's said on Thursday that Bahrain's B1 credit rating will be supported by aid pledged by other Gulf countries this week, as long as it is large and flexible.

Saudi Arabia, Kuwait and the United Arab Emirates said on Tuesday that they would provide funding to struggling Bahrain. 

"New financial commitment from the GCC would provide effective support to the sovereign's credit profile if it is large, given the government's financing needs over the next 12-18 months," Moody's said.

Other requirements are for it to include, "clear conditions and modality of provision, and if it is flexible to ensure that the funds can be tapped in the case of prolonged impaired market access."

Conversely, it said that delays or lack of clarity on the support "would put negative pressure on the sovereign's creditworthiness."

Moody's currently has a negative 'outlook' on Bahrain's junk-grade, B1 rating.

(Reporting by Marc Jones; editing by Claire Milhench) ((marc.jones@thomsonreuters.com; +44 (0)207 542 9033; Reuters Messaging: marc.jones.thomsonreuters.com@reuters.net Twitter @marcjonesrtrs))