Greens co-deputy leader Larissa Waters returned to parliament today for the first time since giving birth to her second daughter in March.
Six-week-old Alia Joy made political history during her debut in the chamber.
She became the first baby to be breastfed in federal parliament.
Breastfeeding has been permitted in the chamber since 2003, but Alia became the first to actually be fed.
"Women have been doing it in parliaments around the world ... It is great to see it is able to occur now in the Senate," Labor frontbencher Katy Gallagher told Sky News.
Waters instigated changes which extended Senate rules that already allowed breastfeeding in the chamber to allow new mothers and fathers to care for their infants on the floor of parliament for short periods of time.