BEIJING (AFP) - China's monthly trade surplus fell 29.6 per cent in July year-on-year to US$17.8 billion (S$23 billion), government data showed on Thursday as imports and exports both rose.

Exports increased 5.1 per cent to year-on-year to US$186 billion, according to customs data, while imports rose 10.9 per cent to US$168.2 billion.

The results marked a rebound in both exports and imports after they had declined in June, with the gain in imports being the first since April.

The trade data come after mixed messages on China's economy last week when private and official surveys of the country's important manufacturing sector showed differing results.

British banking giant HSBC's purchasing managers' index indicated contraction while the government's showed a surprise expansion.

China's economy managed growth of 7.8 per cent in 2012, its slowest since 1999.

The economy has since weakened further, with growth in the April-June period dipping to 7.5 per cent, from 7.7 per cent in the first quarter and 7.9 per cent in October-December.