* SSEC +0.2 pct, CSI300 +0.3 pct, HSI flat

* China volatility index nears lowest level since May

* Some fear concentrated selling after the party congress

SHANGHAI, Oct 13 (Reuters) - China stocks inched up in quiet trading on Friday morning, as investors anticipated markets to remain stable ahead of next week's Communist Party Congress that is expected to stress stability.

With trade volume dwindling, investors gave a muted response to generally upbeat China trade data released on Friday, as well central bank moves to inject nearly 500 billion yuan into the financial system via one-year loans.

The blue-chip CSI300 index rose 0.3 percent, to 3,923.86 points at the end of the morning, while the Shanghai Composite Index gained 0.2 percent, to 3,391.16 points, continuing a pattern of staying in a narrow range.

Although the CSI300 and SSEC have climbed 2.3 percent and 1.3 percent respectively so far this week, most of the gains were achieved on Monday, when the Chinese market played catch-up with bullish global equities following a week-long holiday.

Reflecting the market's relative inactivity, China's volatility gauge - which measures investor expectations of fluctuations in the SSE50 index - has dropped to as low as 10.68 this week, almost touching its lowest since May.

While most analysts expect Chinese stocks to sail smoothly through the party congress, which starts on Oct. 18, as regulators have said maintaining market stability is a major political task, there's concern a sell-off could begin after the meeting.

Beijing's apparent attention recently to restrict massive share-selling has worked to stabilize the market, but the policy also risks sapping market vibrancy and accumulating the risk of a "stampede", Beijing-based Dongxing Securities wrote in a recent note.

Once the restrictions were lifted, "possible intensified selling could trigger a chain of reactions, causing wild market swings," the brokerage said.

Such a view was echoed by Kenny Li, CEO of investment advisor Quattroquant, who is not optimistic on market trends after the congress.

"We would suggest lower allocations to stocks, as we see no reason that supports a further rise in Chinese stocks, especially in big caps."

Sector performance was mixed on Friday morning.

Property shares fell, but consumer stocks continued to rise. The aviation sector jumped 1.4 percent, as investors expect fresh policies to boost it.

HONG KONG

Hong Kong stocks were little changed too.

The Hang Seng index was unchanged at 28,468.76 points, while the Hong Kong China Enterprises Index gained 0.1 percent, to 11,508.68.

The indexes were also roughly flat for the week.

(Reporting by Samuel Shen and John Ruwitch; Editing by Richard Borsuk)