Wesfarmers says full-year earnings from its department stores could fall by as much as $103 million after sales at the struggling Target chain fell by 2.3 per cent so far in the second half.

The Perth-based conglomerate, which reports its full-year results on August 27, says Target's comparable sales for the five months to May fell 2.3 per cent on the prior corresponding period and by 0.7 per cen...