Sonia O'Sullivan could miss the World Cross Country Championships in Lausanne next month.

O'Sulllivan has had to interrupt her winter training regime in Australia due to an Achilles tendon injury.

The Irish runner was forced to withdraw from a big IAAF cross country race in Japan last Sunday having sat out training for several days.

O'Sullivan was due to take part in the Ras na hEireann in Co Louth on 16 March in preparation for the World event a fortnight later.

We simply don't know yet how long this injury will take to clear up Alan Storey

Now there is a big question mark over her fitness.

Her London-based coach Alan Story said it would take several days before they could fully asess the extent of the injury.

''These sort of niggling injuries can disappear as quickly as they arrive,'' said Story.

''Obviously Sonia has been getting as much treatment as possible from Gerard Hartmann's assistant Alison Rose.

''But we simply don't know yet how long this injury will take to clear up.''

If O'Sullivan was forced to withdraw, it would dent the Ireland's women's team from repeating their bronze medal achievement in Leopardstown last year.