Viduka is hoping to secure a pay-as-you-play deal with the Hammers and still aims to play in the World Cup in South Africa for the Socceroos.
Viduka was released by Newcastle at the end of last season and it is understood he tried to re-sign for the Magpies on transfer deadline day.
West Ham released this statement this morning which said: "Gianluca Nani (technical director) and Gianfranco Zola are now discussing the possibility of an out-of-contract striker joining the club who has been tracked in the past month."