HANOI (AFP) - Ratings agency Fitch on Thursday downgraded Vietnams sovereign debt, citing weakness in its external finances and banking system, a highly dollarised economy and inconsistent macroeconomic policy. In a statement, Fitch said it was downgrading Vietnams long-term issuer default ratings on both foreign and local currency from BB- to B+. It criticised the stop-go policy tightening and easing of Vietnamese monetary policy, which Ai Ling Ngiam, director of Fitchs Asia Sovereign team, said was ad-hoc, reactive and inconsistent. The agency said there was a risk of policies easing towards a pro-growth stance, adding to instability, in the countdown to the national congress of the ruling Communist Party in January 2011. Fitch already placed a negative outlook on the countrys rating in March, citing deteriorating confidence in the dong currency and growing inflation risks. Vietnams sovereign credit-worthiness has deteriorated on the back of weaker external finances and rising external financing requirements amid an inconsistent macroeconomic policy framework, a highly dollarised economy and a weak banking system, Ngiam said Thursday. The State Bank of Vietnam (SBV) accumulated more foreign assets from the banking system in the second quarter, the agency said, but Fitch does not believe that Vietnams external finance position has stabilized as yet.