Australia's Rugby Union Players' Association has launched a health and safety investigation after the serious injuries sustained by Matt Dunning and Sekope Kepu in last week's game against the Barbarians at Wembley.
The two props were injured when a scrum collapsed, with Dunning potentially out for up to nine months after undergoing surgery on a ruptured Achilles.
Kepu's chances of featuring in the Super 14 are said to be slim after he tore a pectoral muscle. Both men play for the NSW Waratahs.
The matter has been referred to a six-man health and safety committee made up of representatives from RUPA and the Australian Rugby Union.
RUPA chief executive Tony Dempsey told the Sydney Daily Telegraph: "We're concerned from an occupational health and safety point of view that our members may be asked to play on surfaces that are unstable.
"From discussions I have had it was very, very unstable under foot.
"The employers are the ARU and as such they have a duty of care to ensure safe playing surfaces for the players. It is something definitely worth exploring.
"(The committee) was established to investigate players' safety and welfare and we're looking to see what recommendations can be given to deal with this issue."
No Wembley Stadium officials were available for comment.