The benchmark Hang Seng Index gained 12 points, or 0.05 percent, to open at 24,234 on Thursday.

That came after mainland Chinese stocks opened higher, with the benchmark Shanghai Composite Index up 0.04 percent to open at 3,456 and the Shenzhen Component Index opening 0.18 percent higher at 10,431.

The ChiNext Index, tracking China's Nasdaq-style board of growth enterprises, was up 0.33 percent to open at 2,130.

The Chinese gains came after major US stock indices closed at fresh records on Wednesday following a US-Vietnam trade deal, while oil prices jumped after Iran suspended cooperation with the UN nuclear watchdog.

Both the S&P 500 and Nasdaq finished at records for the third time in four days after US President Donald Trump reached an accord with Vietnam.

"Little by little, we are coming to agreements," said Sam Stovall of CFRA Research. This "should be regarded as positive."

The Vietnam announcement bolsters hopes about additional US trade accords and helped offset a report that showed private-sector US employers shed 33,000 jobs in June. (AFP)