Caretaker coach Rob Howley and forwards coach Robin McBryde both confirmed Gatland's arrival was "imminent" and he was expected to have an input into the final two sessions before Wales take on Australia in Saturday's second Test at the Etihad Stadium.
The 48-year-old Gatland, who is favourite to win the nomination to become the British & Irish Lions coach in Australia next year, was injured in a fall while working at his family beach house on Waihi Beach on Easter Monday
He was cleaning windows when he lost his balance and fell around 10 feet on to concrete, taking the full impact on his heels. He suffered multiple fractures to the right heel bone and also a fracture to the left one.
He had both legs put in casts and underwent surgery to reconstruct his right heel. The injuries meant he has stayed at home in New Zealand ever since and when he arrives it will be the first time the players have seen him since their Grand Slam campaign.
Howley was given the job of caretaker coach in Gatland's absence and coached them to victory over the Barbarians ahead of the tour to Australia.
The win over the Baa-Baas made it six wins in a row this year before the Wallabies won the first of the three tests this month, 25-19 in Brisbane.
Gatland has been on the phone constantly with Howley and his fellow coaches and will arrive a day after Wales beat the Brumbies in Canberra in a midweek fixture.
It has not been confirmed how long he will stay in Australia.
Wales have to win the Melbourne test to keep the three-match series alive. They are chasing their first win over the Wallabies in Australia since 1969, and their first victory over a Tri Nations team away from home since 1987.