(Reuters) - China's short-term foreign debt levels are rising at a worryingly fast pace, although overall risks are under control given the country's war chest of foreign currency reserves, the deputy head of its currency regulator said on Thursday.

Li Chao, vice head of the State Administration of Foreign Exchange, said the ratio of China's short-term foreign debt to total foreign debt is among the highest in the world, but lower than those of Hong Kong and Japan.

The size of our overall foreign debt is not very big and our country's debt repayment ability is sufficient, Li told a forum.

But one indicator is not that pretty, he said, noting that short-term debt accounts for 72 percent of China's overall debt. We should continue to give special attention to short-term debt.

He said the rise in short-term debt is propelled by explosive expansion in trade finance and credit, in line with China's fast-growing exports and imports, although risks could be contained over time as financing deals slow.

China incurred $642.5 billion worth of foreign debt as of the end of June, including $462.1 billion in short-term debt. But the stash of debt is dwarfed by the country's $3.2 trillion foreign exchange reserves.

Li said China's foreign debt-to-GDP ratio of 9.3 percent is well below levels acceptable internationally, and that the debt-to-export revenue ratio is also at a solid 29.3 percent.

Short-term debt soared an average 18 percent between 2001 and 2010, outstripping growth of 11.7 percent in overall debt, Li said.

China's currency regulator has curbed short-term borrowings in recent years under a campaign to crack down on hot money inflows fuelled by a rising yuan.

Such inflows have cooled and there were even signs of outflows since October as turmoil in global markets prompted some investors to leave the country.