BEIJING (AFP) - China's manufacturing activity strengthened in August, official figures showed on Sunday, the latest data to suggest that the world's second-largest economy is stabilising.

The official purchasing managers' index (PMI) rose to 51.0 last month from 50.3 in July, according to figures released by the National Bureau of Statistics.

The index tracks manufacturing activity in China's factories and workshops and is a closely watched gauge of the health of the economy. A reading below 50 indicates contraction, while anything above signals expansion.

The PMI strengthened for the second straight month and comes as other recent data have spurred optimism a slowdown in the economy may have been stemmed.

The first half of this year saw a spike in analyst concerns after an expected rebound from the worst growth performance in 13 years failed to materialise.

China's economy grew 7.8 per cent in 2012, the weakest result since 1999.

Growth in the first three months of the year dipped to 7.7 per cent from 7.9 per cent in the final quarter of last year and slowed further to 7.5 per cent in the three months through June.

British banking giant HSBC said last month that the initial reading of its PMI survey for August came in at 50.1, rebounding from an 11-month low and marking the first time since April the indicator had expanded.

HSBC was due to release its closely watched final PMI index for August on Monday.