Slovenia, the eurozone’s newest member, was on Tuesday warned bluntly by the European Central Bank about soaring inflation and the risk of a damaging boom-and-bust cycle as it adjusted to life in a monetary union.

Lorenzo Bini Smaghi, an ECB executive board member, used uncompromising language to send a shot across the bows of the government in Ljubljana and a signal to other would-be members of the 13-strong eurozone.