HONG KONG, Feb 6(Reuters) - China and Hong Kong stocks advanced on Thursday, driven by the tech sector, as investors continued to bet on domestic artificial intelligence firms following Chinese AI start-up DeepSeek's breakthrough.

** At the midday break, China's blue-chip CSI300 index .CSI300 was up 0.69%, and the Shanghai Composite index .SSEC rose 0.76% to 3,254.12 points.

** The Hang Seng Index .HSI in Hong Kong was trading 0.29 higher at 20,655.94.

** AI-related sectors led gains in both onshore and offshore markets. The CSI Semiconductor Industry Index .CSI931865 surged 4.3% to a five-week high, and the Hang Seng Tech Index .HSTECH climbed 1% to the highest level since last October.

** Shares of chipmaker Naura 002371.SZ surged 7.7%, their biggest single-day advance in nearly three months, while SMIC's Hong Kong-listed shares 0981.HK rallied nearly 6% to a record high.

** Enthusiasm for domestic AI-related firms showed no signs of abating after DeepSeek disrupted the global industry last month with advanced models at low cost.

** "DeepSeek's breakthrough is driving a renewed confidence in China's AI sector and it will continue to be a key market theme," analysts at China Securities said in a note.

** It's challenging the prevailing notion that China lags several years behind U.S. competitors in the AI race, and the sector could chart its own course in a revaluation despite global volatility, they added.

** Around the region, MSCI's Asia ex-Japan stock index .MIAPJ0000PUS was firmer by 0.25% while Japan's Nikkei index .N225 was up 0.43%.

(Reporting by Hong Kong Newsroom; Editing by Sherry Jacob-Phillips)

((jiaxing.li@thomsonreuters.com +852 63358304))