The Scottish Government said it had agreed to a three year trial for the route between Mallaig and South Uist.
However there is disappointment that this will only be on two days a week and during the winter months.
South Uist and Barra are served by the same ferry to Oban. The trip to South Uist can take almost seven hours if it goes to Barra first.
Islanders believe a three-and-a-half hour service to Mallaig would herald a new dawn, now that the Mallaig to Fort William has been upgraded.
Keith Brown said: "I am pleased to announce that following detailed analysis of the availability of vessels across all our Clyde and Hebrides routes, over the next three winter periods we will test the feasibility of the service on a trial basis."
Storas Uibhist, the community-led organisation which owns much of Benbecula, Eriskay and South Uist, had been highly critical of ministers, saw it as the first step in restoring the "Missing Link".
But its statement continued: "We are disappointed that it is limited to two days a week and only for a trial period over the winter months when there is less demand.
"We await with interest the full timetable details to understand the potential impact of the service; many hauliers for example, will need a next day return all year around for it to be cost effective for them and, will not be able to change their shipping contracts easily for short periods."