SINGAPORE —Stocks in Asia-Pacific were mixed on Wednesday, with tech shares in the region monitored following overnight declines for the sector on Wall Street.

In Japan, the Nikkei 225 rose 1.78% to close at 25,349.60 while the Topix index also gained 1.66% to end its trading day at 1,729.07. South Korea’s Kospi added 1.35% to close at 2,485.87.

Mainland Chinese stocks declined on the day. The Shanghai composite shed 0.53% to around 3,342.20 while the Shenzhen component declined 1.952% to about 13,720.17. Hong Kong’s Hang Seng index dipped 0.28% to finish its trading day at 26,226.98.

Shares in Australia rose, with the S&P/ASX 200 up 1.72% to close at 6,449.70.

MSCI’s broadest index of Asia-Pacific shares outside Japan was fractionally higher.

Tech shares in the region were watched after their counterparts on Wall Street saw declines overnight. Hong Kong-listed shares of Chinese tech firms were among the hardest hit on Wednesday.

Hong Kong-listed shares of Chinese tech giants Alibaba and Tencent dropped 9.8% and 7.39%, respectively. JD.com also fell 9.2% while Meituan declined 9.67%.

That came after China’s State Administration for Market Regulation on Tuesday announced a set of draft guidelines aimed at curbing monopolistic behavior on internet platforms. The broader Hang Seng Tech index fell 6.23% on the day to 7,465.44.

Elsewhere in Japan, shares of conglomerate Softbank Group slipped 2.47%. Over in South Korea, industry heavyweight Samsung Electronics saw its stock gain 1.83%.

Investor focus likely remained on the coronavirus situation, following a positive announcement on Monday by Pfizer and BioNTech regarding a potential vaccine. Still, the number of cases globally continued to rise rapidly.

“A rotation theme remains evident in equity markets,” Rodrigo Catril, a currency strategist at National Australia Bank, wrote in a note. The recent vaccine development from Pfizer and BioNTech has “triggered a reassessment of the outlook for next year,” he said.

“Big tech which has benefited from our virus driven change in behaviour (working from home a primary example) is now falling out of favour while small cap stocks and those that have been most affected by social distancing restrictions have outperformed,” Catril said.

Oil prices were higher in the afternoon of Asia trading hours, with international benchmark Brent crude futures up 2.45% to $44.68 per barrel. U.S. crude futures added 2.59% to $42.43 per barrel.

The U.S. dollar index, which tracks the greenback against a basket of its peers, was at 92.823 after rising from levels below 92.4 earlier this week.

The Japanese yen traded at 105.45 per dollar, still off levels below 104.3 against the greenback seen earlier in the week. The Australian dollar changed hands at $0.7288, higher than levels below $0.72 seen last week.

— CNBC’s Karen Gilchrist contributed to this report.