BEIJING (Reuters) - Two sets of data out Wednesday reinforced signs of a slowdown in the world's second-largest economy that could prompt more stimulus measures.

Growth in China's services sector weakened slightly in September as new business cooled, a private survey showed. The services purchasing managers' index (PMI) compiled by HSBC/Markit pulled back to 53.5 in September from a 17-month high of 54.1 in August. A reading above 50 in PMI surveys indicates an expansion in activity while one below that threshold points to a contraction.

An official survey released last week showed that the services sector grew at its slowest pace in eight months in September after new orders shrank for the first time since the 2008 global financial crisis, exposing more weakness in China's economy.

The services sector made up 46.1 per cent of gross domestic product in 2013, surpassing the secondary sector - manufacturing and construction - for the first time, as the government aims to create more jobs and boost domestic consumption.

Also slowing was the growth in China's retail sales during the key week-long "Golden Week" holiday. That dropped to 12.1 per cent from a 13.6 per cent rise in the same period last year, according to data from the Ministry of Commerce.

Analysts were closely watching consumption during the holiday, which ran from Oct 1-7.