In 35 BC, Vetus was given command of the ongoing war against the Salassi, perhaps as the governor of Transalpine Gaul, which he prosecuted with vigour, but without success. Then in 30 BC, he was awarded the position of consul suffectus, serving alongside Octavianus for a portion of the year. Vetus was then made legate of Hispania Citerior in 26 BC, one of the few men of consular standing to be given a military province during the reign of Augustus. He took over from Augustus after the Princeps fell ill whilst on campaign in Spain, leading a campaign together with P. Carusius against the Astures which they successfully concluded in 25 BC.