KINGSTON, Jamaica — Defending Beijing 2008 gold medalist Melanie Walker will face strong threats from Natalya Antyukh (Russia), the fastest 400m hurdler this year, and 2011 world champion Lashinda Demus (USA) at the London 2012 Olympic Games.

Demus is looking to add Olympic gold to her 2011 world title and two world silver medals. The athlete took gold from Walker in Daegu, Korea, last summer as Walker had to settle for second. She would be the first USA athlete to win gold in this event.

Walker will be the first female athlete to achieve gold twice in the 400m hurdles if she can repeat her Beijing victory, but she is yet to run under 54 seconds this season. She also won the 2009 world championships title.

Antyukh took third at the 2011 world championships in Daegu. The Russian champion tops the 2012 world list with a best time of 53.40 from the national championships in Cheboksary in July.

European champion Irina Davydova (Russia) is likely to challenge the favourites at her first Olympics. She ran 53.77 to win in Helsinki, while Perri Shakes-Drayton (Great Britain) will also have her eyes on a medal after beating Davydova at the London Diamond League meeting, recording a personal best of 53.77.

Shakes-Drayton and Davydova are in equal second place on the 2012 world rankings. The former, the 2010 European bronze medallist, also won a world indoor championships gold medal with Britain's 4x400m relay team in Istanbul in March.

Vania Stambolova (Bulgaria) will try to add an Olympic hurdles medal to the world indoor championships silver medal and European championships gold she has won at 400m, both trips to the podium coming in 2006. She lowered her own 400m hurdles national record to 53.68 last year and is close to 54 seconds in 2012.

Also, Czech champion and 2011 European indoor championships 400m gold medal Denisa Rosolova, a silver medallist at the 2012 European championships recently, could also be a contender despite still learning her trade in her first serious year at the event.

Rosolova’s compatriot Zuzana Hejnova beat Demus at the Monaco Diamond League meeting on 20 July and the Beijing 2008 finalist has a season's best of 54.12.

The event starts tomorrow.