China's foreign currency reserves rose at their slowest pace in 18 months last month in what analysts said was new evidence that speculative demand for the yuan may be ebbing.

According to China Business News, however, there was still a US$9.3 billion increase in the reserves, the world's biggest after Japan's, to a record US$794.2 billion.

The paper has previously reported the reserves accurately before their official release, normally at the end of each quarter.

"The market still expects the yuan to appreciate, but the expectations have weakened a bit," said Xiao Minjie, an economist at Daiwa Institute of Research.

The reserves rose US$15.9 billion in October, according to the paper, compared with a $15.8 billion increase in September.

The report did not say if last month's slowdown reflected an inaugural, US$6 billion, one-year currency swap that the central bank did with a group of domestic banks last month. Economists said the data confirmed a slowing trend since monthly reserve accumulation peaked at US$36 billion in December last year over yuan bets.

Last month was the first since May last year in which the reserves grew by less than US$10 billion.

Since a landmark 2.1 per cent revaluation of the yuan in July, the central bank has been trying to cool the revaluation speculation by rejecting talk of another one-off adjustment and keeping domestic interest rates low.

However, Mirza Baig, a currency strategist at Deutsche Bank, said the slowdown could be the temporary reflection of a strengthening US dollar, which had lessened upward pressure on the yuan.

If the dollar reverses course, the pace of reserve accumulation could accelerate again, he said.

The country's reserves have ballooned in recent years as the central bank - to hold down the yuan - has bought most of the dollars generated by a growing trade surplus, a headlong rush of foreign direct investment and inflows of speculative capital.