Corticosteroids, which are used in anti-inflammatory medicines to treat a range of conditions, are allowed out of competition by athletes and permitted in competition by obtaining a therapeutic use exemption.
Last year Carter, along with Racing 92 team-mates Rokocoko and Juan Imhoff, created international headlines when traces of corticosteroids showed up in drugs tests taken by the trio following last season's Top 14 final in Barcelona.
However, they were cleared of anti-doping breaches by the French Rugby Federation last October who ruled that the trio had not broken any rules in treating their injuries.
At the Tackling Doping in Sport conference in London, Wada director general Olivier Niggli said the status quo was an "unsatisfactory situation'' and a group of experts will now look into whether corticosteroids are being abused.
The UK Anti-Doping Agency wants corticosteroids to be outlawed.
UKAD chief executive Nicole Sapstead says "there is always the risk that when a substance isn't banned'' that someone "is trying to gain advantage.''
Bradley Wiggins, the 2012 Tour de France winner, faced questions last year after the Fancy Bears hacking group showed he had medically approved corticosteroid injections to prevent hay fever.
Photo: REUTERS (The medicine that led to a positive drugs test for Dan Carter could soon be outlawed by Wada).