Streakers face hefty fines at Olympics

Streakers have been warned that cheeky business at next year's Olympics could result in fines of up to STG20,000 ($A31,000).

Harsh penalties have been put in place to deter streakers from flashing advertisements in a crackdown on ambush marketing at the London Games.

Olympic sponsors plough hundreds of millions of dollars into the quadrennial sporting extravaganza and organisers fear their investments being undermined.

London Olympic organisers are reportedly investigating about 50 ambush marketing cases a month with concerns that developments in social media are outpacing the law.

Exhibitionists conducting marketing stunts in and around Olympic venues during next year's Games may face criminal charges, according to the British media.

Perpetrators will be presumed guilty with the presumption of innocence suspended for such activities.

They must show they had no knowledge of the activity or took reasonable steps to stop it.