China's short-term foreign debt jumped 24 percent in the March-June quarter, possibly indicating speculative money inflows in anticipation of a stronger yuan.
The rise, to $343.8 billion, might also be a reflection of lower dollar borrowing costs, according to analysts.
Short-term foreign debt made up 66.9 percent of China's total debt, up from 62.3 percent at the end of March, the State Administration of Foreign Exchange said on Saturday.
In April, the regulator cut the short-term foreign debt quota for 2010 to prevent "abnormal" capital inflows.
China's overall foreign debt rose 16 percent to $513.8 billion at the end of June. China's foreign exchange reserves are almost five times larger.
This was one of the reasons cited by Moody's Investors Service on Friday for its decision to put China's government bond rating under review for a possible upgrade.
Of the total debt, 72 percent is denominated in dollars, up 4.3 percentage points from the end of 2009, the regulator said on its website, www.safe.gov.cn.