Under DFSA rules, which apply to companies operating within the Dubai International Financial Centre framework, firms offering Islamic services must have a Sharia supervisory board made up of "competent" scholars.
But speaking at the Middle East Investment Summit in Dubai yesterday, Mr Gray said he believed Islamic finance scholars should also be regulated.
"It happens with lawyers and accountants and doctors, why not scholars? They are as fallible as the rest of us."
A lack of standardisation among scholarly opinion led to confusion and ran the risk of "scholarly arbitrage", with "some firms minded to seek the view of a scholar whom they regard as being sympathetic to their product", Mr Gray said.
The small pool of scholars, estimated to be about 140 across the Islamic finance sector, means many sit on several supervisory boards - some as many as 100 boards - which gives rise to claims of conflict of interest, said Azeemuddin Subhani, a Sharia scholar and a professor of Islamic finance at the University of Ajman.
He added the number of finance boards a scholar could sit on should be capped. "The question is not a cap on their earnings but a cap on the number of boards they can sit on. If you are sitting on the boards of even five different banks you can see the potential conflict of interest."
Islamic finance should use the regulatory rebuilding around the world to formalise standards for its industry and increase its global foothold, said Mr Gray.
"Conventional standard-setters still have their hands full with the crisis … That gives the Islamic finance world time to get its house in order," he said. "But if it does not do so, then … it will face more powerful conventional regulatory bodies that will do the job for it. The clock is ticking."