China's Communist Party has started a key meeting to decide long-term economic policies, amid growing uncertainty over the country's economic outlook.

The third plenary session of the party's Central Committee got underway in Beijing on Monday, under tight security.

The talks are largely focused on "overall deepening of reforms" and "promotion of Chinese-style modernization."

The meeting is taking place as China's property market has slumped, and domestic demand is sluggish.

Observers are watching closely what kind of policies the leadership of Chinese President Xi Jinping will set forth.

They include measures to address financial risks and worsening local government finances due to the battered property market, as well as nurturing new industries to replace the real estate sector.

Observers are also waiting to see whether there will be a reshuffle of senior party posts. A media outlet in Hong Kong says the talks may see former foreign minister Qin Gang and former defense chief Li Shangfu removed from the party's Central Committee. Both were fired from the Cabinet last year.

The closed-door talks will run through Thursday. A communique is scheduled to be released on the final day.