SHANGHAI, Feb 20 (Reuters) - China's stocks closed up on Tuesday, rebounding from losses in early trade, after the country announced its biggest ever reduction in the benchmark mortgage rate to prop up the struggling property market and broader economy.

The blue-chip CSI300 Index ended 0.2% higher, rising for a sixth straight session, while Hong Kong's Hang Seng benchmark finished up 0.6%.

China's five-year loan prime rate (LPR) was lowered by 25 basis points to 3.95%, while the one-year LPR was left unchanged at 3.45%.

The cut "was the first cut in eight months, and the largest since that rate was introduced in 2019", said Andy Maynard, head of equities at China Renaissance in Hong Kong.

It's "very positive for the market", he said.

The rate cut, which influences the pricing of mortgages, sends a strong signal that policymakers are serious about providing more support to the property market, said David Chao, global market strategist for Asia Pacific ex-Japan at Invesco Asset Management.

Shares in real estate developers rose 1%, and securities brokers added 1.3%.

In Hong Kong, tech giants added 0.4%, after rising 6.9% in the previous week, and mainland property developers climbed 0.8%.

Also helping sentiment, China's securities watchdog said it held a series of seminars with market participants who proposed tighter scrutiny of company listings and trading behaviour.

The meetings were led by the watchdog's newly installed chairman Wu Qing and held immediately after the week-long Lunar New Year holiday.

Still, investors doubt a recent rally in stock market can last, even after efforts by authorities to shore up confidence, and analysts say more strong measures are needed.

"I don't think this will be sufficient, I think you need to have a good macro policy mix of both fiscal and monetary policy," said Saktiandi Supaat, regional head of FX research and strategy at Maybank.

"So the fiscal stimulus element is still missing to play a role to enhance sentiment." (Reporting by Shanghai Newsroom, Editing by Sam Holmes and Ed Osmond)