SHANGHAI, July 15 (Reuters) - China stocks edged down on Friday, dragged by property developers, as homebuyers' threats to stop mortgage payments on unfinished apartments dented sentiment, despite Beijing's assurance to solve the crisis.

Losses were capped by strong performance in consumer stocks, after data showed a surprising rise in retail sales, and as dismal economic growth in the second quarter raised expectations of more stimulus.

The CSI300 index fell 0.1%, to 4,320.11 points at the end of the morning session, while the Shanghai Composite Index lost 0.2%, to 3,273.87 points.

Growing numbers of homebuyers have threatened to halt mortgage payments until developers resume construction of pre-sold homes. The protest threatens to stall a nascent recovery in China's capital-starved property sector and hit banks with hefty writedowns, analysts said.

Chinese regulators on Thursday vowed to help local governments deliver property projects on time, while at least 10 banks said mortgages related to risky property projects are relatively small, and risks are controllable.

In mainland markets, real estate developers tumbled more than 5% and banks lost 1.4%, while mainland developers listed in Hong Kong slumped roughly 3% to a 10-year low.

China's gross domestic product (GDP) rose 0.4% year-on-year in the second quarter, missing expectations, as widespread lockdowns to curb record COVID cases hit industrial activity and consumer spending.

"The economy likely bottomed in Q2. It is on track for a slow recovery," said Zhiwei Zhang, Chief Economist at Pinpoint Asset Management.

Consumer staples gained 1.1% and consumer discretionary stocks added 1.5% after data showed retail sales rose 3.1% following the easing of COVID-19 restrictions last month. Analysts had expected flat sales after May's 6.7% drop.

"The retail sales data is better than expectations," said Linus Yip, chief strategist at First Shanghai Group, picking the economic recovery to gain momentum.

Chinese Premier Li Keqiang said the government will support the economy while preventing inflation, state media reported on Thursday, signalling increased concerns over price rises.

"Given the tame growth, China's government is likely to deploy economic stimulus measures from now on to rev up its flagging growth," said Toru Nishihama, Chief Economist at Dai-ichi Life Research Institute, adding hurdles are high for its central bank to cut interest rates further.

The Hang Seng index dropped 1.2%, to 20,503.58 points. The Hong Kong China Enterprises Index lost 1.2%, to 7,040.35.

Big tech companies traded in Hong Kong 2%, with Alibaba down down nearly 4% after the Wall Street Journal reported the tech giant's cloud division has been summoned by Shanghai authorities in connection with a theft of police data. (Reporting by Shanghai Newsroom; Editing by Amy Caren Daniel and Lincoln Feast.)