The couple – no longer working royals and visiting in a private capacity – are combining visits to charitable causes with commercial ventures.
It is understood Meghan is exploring the Australian expansion of her As Ever lifestyle brand during the trip.
Later on Wednesday, the Duke visited the capital, Canberra, where he took part in a traditional Smoking Ceremony at the Australian War Memorial.
Harry laid a wreath and wafted smoke at the For Our Country memorial, which commemorates Aboriginal and Torres Strait Islanders’ military service.
In Melbourne, Harry was at the launch of a report into the mental health of fathers of young children, by the charity Movember.
After introducing himself with a “G’day everyone”, the Duke talked about his own mental health after becoming a dad – with references to his father, King Charles III.
“The world around us has changed massively, so there is no version of where parenting is going to be the same as we experienced,” he said.