The credit ratings of most Asian nations remain sound despite the debt problems in Europe and the United States, with the notable exception of Japan, a senior official at Standard and Poor's ratings agency said on Wednesday.

Takahira Ogawa, S&P's director of Asian sovereign ratings, said the substantial holdings of Asian nations of U.S. Treasury notes and bonds may be affected by a possible U.S. downgrade, but it would not affect their credit standing.

On the whole, the general perception of investors at this stage is that the Asian economic credit story is positive, he told Reuters, adding that most Asian sovereign ratings were on an uptrend.

If you compare to the other mature economies, like the euro zone and the United States, there is still a potential growth story (in Asia).

On the risks of contagion, Ogawa said a big shock in Europe would hit the flow of investment funds to Asia, and could also affect Asian exports. But he said the exposure of Asian banks to European debt, especially that of peripheral nations, was minimal.

On U.S. debt problems, he said the major risk would have been a default, but this had been averted after a last-ditch deal at the weekend before an Aug 2 deadline.

The second risk (lingering U.S. fiscal problems) still remains, but this is a more medium term challenge, so there is no immediate implication.

It might not be fixed any time soon. That doesn't necessarily mean the world is over. It doesn't necessarily mean that Asian sovereigns are in danger because of this situation.

Markets are waiting to see if S&P will downgrade U.S. sovereign credit after the new debt deal, which did not cut future spending as much as the rating agency had said would be needed to support the prized AAA rating.

Ogawa said markets to some extent have already discounted the potential risk of a U.S. downgrade.

Turning to Japan, Ogawa said that country's debt problems had intensified in recent months, but not to the extent that further ratings action was warranted.

The situation is most probably getting worse. There is no progress in the structural reform, there is no progress in the fiscal consolidation. The deterioration of Japan's credit still continues.

We see Japan sovereign risk still increasing but not to the extent for us to have another action.

In April, S&P affirmed Japan's rating at AA-minus, but with a negative outlook, warning it risked a downgrade since the huge cost of the devastating March earthquake and tsunami would hurt already weak public finances unless bickering politicians agreed to raise taxes.

Ogawa also singled out Vietnam as another Asian nation where ratings were not on the uptrend, but did not elaborate.

However, countries which had a relatively larger proportion of foreign funds in their debt portfolio were more vulnerable to external shocks, he said, naming Indonesia, the Philippines and South Korea among such nations in Asia.

Referring to Indonesia, Ogawa said: Because of the small capital market and foreign exchange market, a small number of outflows of funds can affect quite significantly on the foreign exchange and capital market valuations.

These things we also need to take into account.

BlackRock, the world's largest money manager, also said Asian economies were in good shape, although there were worries about inflation and the possibility of a fight for capital if debt problems in the West worsened.

From a fundamental standpoint, we see the Asian economies are in a pretty sound shape although we do think there is a slowdown, Neeraj Seth, BlackRock's head of Asian credit, told reporters.

Although inflation was also a risk, he added: We still believe there are long-term opportunities in Asia. But it is not free of these risks.

(Additional reporting by Harry Suhartono; Writing by Raju Gopalakrishnan; Editing by Kim Coghill)

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