China's stock markets roared back from a week-long break and climbed to their highest levels in more than two years at the open, but lost steam after officials failed to inspire confidence in stimulus plans intended to turnaround a sputtering economy.

A rally in onshore Chinese stocks on their return from a week-long holiday cooled as traders questioned Beijing’s resolve to add more stimulus. Shares in Hong Kong tumbled.

Shares in mainland China soared at the opening, as markets reopened after the Golden Week holidays. But they slid back as the stimulus plans provided by China's economic planning agency seemed to underwhelm investors.