St Helen's Farm is providing the milk in whole and semi-skimmed format and has listings in Sainsbury and Safeway.
The company has invested in new dairy systems and improved packaging technology which has allowed them to extend the milk's shelf life by two days.
According to St Helen's Farm, the goats milk market has risen by 50% over the past four years and demand for its products grew last year by 8.5%.
Mike Hind, marketing manager, said: "We place great emphasis on listening to what our consumers want and we have had a high number of requests for a larger carton of milk in both varieties.
"We are hoping that the increased pack size will help to satisfy the increased consumption levels of goats milk and that it will also improve on-shelf availability.
"Constant availability of goats milk is essential for people who are following a dairy free diet."
The one -itre packs went into Sainsbury and Safeway this week, with an rrp of £1.19.