Hong Kong and mainland stocks soared again on Monday, extending last week's surge after Chinese authorities unveiled a raft of measures aimed at kickstarting the world's number two economy.

The Hang Seng Index rallied 2.4 percent, or 501 points, to 21,133, a near 20-month high.

Turnover topped HK$500 billion, a fresh record high.

Developers were among the best performers, with Kaisa rocketing more than 80 percent, Sunac jumping 55 percent and Agile Group almost 20 percent stronger.

Tech firms were also enjoying a healthy run-up, with e-commerce giant JD.com climbing 10 percent and rival Alibaba up 7 percent.

On the mainland, the benchmark Shanghai Composite Index surged 8 percent to 3,336 -- its best day since 2008 -- and the Shenzhen Component Index soared more than 10 percent to close at 10,529.

Over the weekend, Beijing moved forward with the stimulus measures announced last week to support the property industry and the financial markets.

The central bank announced on Sunday that it would direct banks to cut mortgage rates for existing home loans by October 31.

Meanwhile, Guangzhou lifted all home-purchase restrictions over the weekend, while both Shanghai and Shenzhen revealed plans to ease key buying curbs.

Days earlier, Beijing unveiled a raft of stimulus measures, including lower bank reserve requirements, reduced interest rates and smaller minimum down payments for some mortgages.

Analysts said the downturn in the property sector has rippled throughout the economy, hitting other industries. (Agencies)