Hong Kong stocks rallied more than three percent at the open of business Friday, building on a huge surge this week fuelled by a series of Chinese measures aimed at kickstarting the economy.

The Hang Seng Index jumped 3.17 percent, or 631.67 points, to 20,556.25 -- the first time it has broken 20,000 since August.

The Shanghai Composite Index added 2.17 percent, or 65.19 points, to 3,066.14, and the Shenzhen Composite Index on China's second exchange advanced 2.27 percent, or 37.24 points, to 1,675.33.

Beijing on Friday announced it had cut the amount of cash banks much hold in reserve -- to boost lending -- having flagged the move earlier this week along with a batch of other stimulus including support for the property sector, interest rate cuts and pledges to boost jobs.

The gains were across the board, with developers soaring and the tech sector also enjoying huge buying interest, while casino operators were also well up.