Hong Kong's superstar swimmer Siobhan Haughey on Wednesday advanced to the 100m freestyle semi-finals at the World Aquatics Championships in Budapest, in one of her last races before taking a break to ponder her future.

Her time of 52.12 seconds topped her heat, and was good for second overall behind American Gretchen Walsh, who clocked a 51.64-second finish.

Haughey, 27, was second at the first turn in the short course race and overtook Briton Freya Andersen shortly afterwards.

Fellow SAR swimmer Li Sum-yiu, 15, was unable to advance after finishing eighth in the same heat with a time of 53.41 seconds.

The semi-finals are due to begin at 0:48am on Thursday, Hong Kong time.

Haughey will also be looking to defend her 200m freestyle title in Hungary.

The four-time Olympic medallist for Hong Kong, China recently announced that she will be taking a few months off from the sport in the new year.