Chinese stocks closed higher Wednesday despite the release of a private survey that indicated slower expansion in the country's service sector in June.

The benchmark Shanghai Composite Index went up 0.76 percent to close at 3,207.13 points, the first time the index exceeded 3,200 since mid-April this year.

The smaller Shenzhen index closed 0.82 percent higher at 10,561.09 points.

The ChiNext Index, which tracks China's NASDAQ-style board of growth enterprises, gained 0.39 percent to close at 1,836.63 points.

The insurance industry led the gains, with Ping An Insurance closing 5.22 percent higher and New China Life Insurance rising 7.27 percent.

Wednesday's gains came after a private survey showed that China's service sector growth cooled slightly in June but still remained in expansionary territory.

The Caixin General Services Purchasing Managers' Index fell to 51.6 from May's four-month high of 52.8, according to a survey conducted by financial information service provider Markit and sponsored by Caixin Media Co. Ltd.

A reading above 50 indicates expansion, while a reading below 50 represents contraction.

Despite the slowdown in growth momentum, Caixin said services companies' confidence towards the year ahead improved slightly in June. The 12-month business outlook edged up to a five-month high in June, with some firms linking positive expectations to new projects and forecasts of improving new order intakes.