HONG KONG, Jan 17 (Reuters) - China and Hong Kong stocks edged lower on Tuesday, as Beijing released weak GDP growth and economic activity data for the fourth quarter, and investors sold on gains ahead of the Lunar New Year holidays.

** China's blue-chip CSI 300 Index dipped 0.02%, while the Shanghai Composite Index declined 0.1%, retreating from a four-month high.

** The Hang Seng Index fell 0.78%, snapping a four-day rally, while the Hang Seng China Enterprises Index slid 0.49%.

** China's economy grew 2.9% in October-December from a year earlier, data from the National Bureau of Statistics (NBS) showed on Tuesday, slower than the third-quarter's 3.9% pace, as the fourth quarter was hit hard by stringent COVID curbs and a property market slump.

** China's property investment fell 10.0% year-on-year in 2022, the first decline since records began in 1999, and property sales slumped the most since 1992.

** Weak population data added to the market concerns - China's population in 2022 fell for the first time since 1961.

** Economists expect China's economy likely bottomed out in December and a recovery is on its way in 2023. They, however, flag risks persist in the property sector, local government debt and disappearing demographic dividend.

** "December might be the bottom of Chinese growth trajectory in the near term," said Chaoping Zhu, Shanghai-based global market strategist at J.P. Morgan Asset Management. "We expect to see a sustained economic recovery in 2023 as a result of reopening and policy stimulus."

** Urban workers crowded train stations across China's largest cities on Tuesday as the country's mass migration for Lunar New Year holidays hit high gear, an early sign of economic rebound.

** Zhiwei Zhang, chief economist at Pinpoint Asset Management, however, warns China's population will likely trend down from here in coming years. "Going forward demographics will be a headwind. Economic growth will have to depend more on productivity growth, which is driven by government policies," he said.

** The insurance sector lost 1.3% on declining population. China Life declined 3.6% in its A-shares and 3.2% in Hong Kong.

** Semiconductors jumped 2.5% and defense stocks climbed 0.9%.

** In Hong Kong, tech firms dropped 0.14%. (Reporting by Summer Zhen; Editing by Nivedita Bhattacharjee and Subhranshu Sahu)