The SAR's Olympic silver medalist Siobhan Haughey on Sunday broke the Hong Kong record for 50-metre breaststroke with a time of 30.46 seconds in her heat at the Asian Games in Hangzhou.

But she was just a bit slower than China's Tang Qianting, who clocked 29.92 seconds, a new Asian record in an earlier heat.

Speaking to Hoy TV afterwards, Haughey said she was happy with her performance.

"I'm very happy because it's my best time. I believe it's also a Hong Kong record."

It's a good start if I can perform like this. I hope I can swim even faster. I feel the other swimmers will also swim faster so the competition will be quite intense."

Haughey had set the previous Hong Kong record for 50-metre breaststroke in March with a time of 31.21 seconds.

She won two silver medals at the Tokyo Olympics – for the 100-metre and 200-metre freestyle events.

The Asian Games women's 50-metre breaststroke final will be held at about 8.30pm local time.