The agency for the Marlborough producer was previously held by PLB, which said it would continue to work with Ara on "special projects".
Ara’s premium Resolute and Composite ranges will be available from DGB with immediate effect, as well as the newly launched Pathway which carries an RRP of £7.99 to £9.99.
Ara commercial director Sue Henderson said: "New Zealand and South Africa are the two countries that are showing growth in both volume and value on the UK market at the moment, and we believe this will continue.
"We have decided to work with DGB because they have a proven track record in developing brands for the challenging UK marketplace.”
Established in 2001, Winegrowers of Ara has a 1,500 hectare vineyard at the confluence of Marlborough’s Wairau and Waihopai rivers.
DGB is best known for the Douglas Green, Bellingham and Boschendal brands from South Africa.