Australia's sixth-largest wine company, McWilliam's Wines, has been forced to seek an urgent capital injection and embark on asset sales after breaching some of its lending covenants as the company sank to an annual loss of $5.5 million.

McWilliam's, owned by 70 family members and with a history stretching back to 1877, has been through a tough time when it shifted its bottling line and packaging operations from suburban Sydney to the Riverina region in NSW, while drought conditions across the Riverina and Hunter Valley hurt vineyard yields.