The appointment, which was made without a competitive pitch, will entail WFCA creating a pan-European press campaign for the brands.
The agency has already created a series of ads for Beringer, which emphasise the label's North Californian roots.
The £300,000 campaign, which features the strapline, "Pioneering great taste since 1876", will run in broadsheets and weekend supplements from October.
WFCA will concentrate on the Italian Castello di Gabbiano wine brand next, creating a campaign that will emerge next year.
Media planning and buying duties for the brands, handled by Universal McCann, are unaffected by the appointment of WFCA.
James Lousada, marketing director at Foster's EMEA, said: "We appointed WFCA because of their ability to understand the nuances of the Premium wine category and as a result provide strong strategic platforms from which to build excellent creative work."
Apart from Foster's lager, the Foster's Group also owns a number of Australian wine brands including Wolf Blass, Penfolds, Rosemount and Lindemans.
Established in 1876, Beringer is one of the leading premium wine brands in the US and originates from the Napa Valley, California.