Wallaby prop Benn Robinson has made his first tentative running steps in his bold bid to make a miracle comeback for the World Cup.

Robinson joined Australia's extended Test squad in camp on the Gold Coast on Friday and underwent fitness testing on his injured knee by medical staff in the afternoon.

The 42-Test prop, regarded as one of the best loosehead props in the world, ruptured his anterior cruciate ligament just 17 days ago, but has by-passed a knee reconstruction.

Robinson is holding a slim chance, at best, of recovering quickly enough to play in the World Cup, kicking off September 9 in New Zealand, but is rolling the dice.

In a positive preliminary assessment, he spent 20 minutes in the gym and between 10-15 minutes running at The Southport School without any ill-effects.

The Wallabies medical staff will assess Robinson again on the weekend after he has a second run on Saturday, but aren't expected to make a World Cup ruling until later weeks.

Fellow injured front row forwards James Slipper (ankle) and Tatafu Polota-Nau (knee) are hopeful of making their returns from the sidelines at the end of the month, along with winger Drew Mitchell (ankle) and No.8 Wycliff Palu (shoulder, knee).