BEIJING - Business activity in China's service sector accelerated to an 11 month high in July, supported by a further increase in new business volumes, a private survey showed on Wednesday.

The Caixin China General Services Business Activity Index came in at 53.8 in July, up from June's 51.8, due to rising business volumes and solid new order growth.

Anecdotal evidence suggested that stronger underlying client demand and new customer wins led to increased new work at service providers, according to the Caixin report.

The Caixin China Composite PMI data, which covers both manufacturing and services, signalled a further increase in activity during July, but the Composite Output Index posted only fractionally above the neutral 50.0 mark at 50.2, the weakest rate of expansion in 14 months.

The report attributed the slower output rate to the manufacturing sector, which registered the quickest reduction of output since November 2011.

The Caixin data on Monday showed China's manufacturing activity retreated to a two-year low in July due to less output and fewer new orders.