Wallabies squad member Luke Morahan has been sent for scans after injuring his right knee in Australia's opening match of the Gold Coast international rugby sevens tournament.

Morahan was subbed off in the opening minutes of the 31-14 win over Tonga and is believed to have sustained medial ligament damage.

The Queensland Red had only just returned to join the sevens team after travelling to Argentina to be a part of Australia's injury-hit Wallabies squad against the Pumas.

It's unclear how severe the 22-year-old's injury is or whether he'll play any further part in the tournament.

Australia's next match in the round robin stage of the two-day tournament is against Scotland from 4.20pm AEST.