Hong Kong's Hang Seng Index rose more than 3.3% in morning trade.
It was the first opportunity investors there had to react to US President Donald Trump's announcement last week that Washington would "begin the process of eliminating policy exemptions that give Hong Kong different and special treatment" from mainland China.
Experts have pointed out, though, that Trump's action will likely have little immediate impact because Hong Kong does not export a lot of goods to the US.
Over the weekend, the Chinese government also reported that its official manufacturing PMI grew in May. The official non-manufacturing PMI survey, which measures the services sector, also indicated expansion — another suggestion that domestic economic activity is recovering, according to Jeffrey Halley, senior market analyst for Asia Pacific at Oanda.