SINGAPORE - Organiser of this year's Osim Sundown Marathon have extended the registration window until Thursday (May 19) due to strong demand.

As of Wednesday (May 18), more than 27,000 runners had signed up for the May 28 race at the F1 Pit Building. Last year's edition saw 26,500 participants.

Said Adrian Mok, managing director of organiser HiVelocity: "The participation numbers from overseas has exceeded expectation and this is in line with our effort to expand the event regionally. It's also a testament that our event appeals to the overseas runners."

Foreigners currently comprised about 43 per cent of race entrants, up from 2015 (39 per cent) and 2014 (35 per cent).

All seven categories will be opened though HiVelocity added that there may be a delay in delivery of certain sizes of race singlets while extra orders are placed to cope with the increase in demand.