LONDON, April 4 (Reuters) - Global securities watchdog IOSCO on Thursday proposed detailed guidance on how regulators should supervise stock exchanges more closely to negate risks from changes in business practices.

"These may give rise to potential risks and challenges concerning the regulatory functions and responsibilities of exchanges, as well as supervisory issues," IOSCO, which comprises securities regulators from across the world, said in a report.

(Reporting by Huw Jones Editing by David Goodman)