The Hang Seng surged either side of the midday break and was last up 7%, and heading for a weekly gain of more than 10% for the first time since November 2011. The Shanghai Composite rose 2.7% and was headed for a 5.6% weekly gain, the largest in more than two years.

Bloomberg News reported initial U.S. inspections of audit papers at U.S.-listed Chinese companies - a long-running point of regulatory tension and risk - finished ahead of time, raising hopes that the U.S. officials were satisfied.

Unsubstantiated social media posts flagging an aim to relax COVID rules in March have also driven optimism all week and seemed to get new momentum on Friday from the appearance of Guang Zeng, former chief expert of epidemiology, at a Citi investor conference on the topic of China's exit from zero-COVID.

"The optimism right now is basically a removal of certain types of uncertainties that have been lingering ... but the outlook is really mixed," said Peiqian Liu, China economist at NatWest Markets in Singapore.

Changes to COVID policies have not been officially flagged and were forcefully dismissed by a foreign ministry spokesman earlier in the week. An early conclusion to audit checks has not been confirmed by either Chinese or U.S. officials and the Bloomberg report carried no comment from either side.

"I think that probably explains why Alibaba is up 20%, not 80%... but that can't discount the optimism we see right now," said Liu.

Alibaba shares were last up 13%. JD.com shares also rose 13%. The Hang Seng Tech index rose 8%. Onshore the blue-chip index rose 3.3%.

The yuan rose about 0.9% to 7.2410 per dollar, despite broad dollar gains elsewhere. [CNY/]

(Reporting by Tom Westbrook. Editing by Sam Holmes)

By Rae Wee and Summer Zhen