From this article on Cinematography Mailing list
Unfortunately, there’s no way to fix this after the fact, and of course you can’t see it on LCD monitors which don’t have rasters. An expensive lesson, but you won’t ever do it again. I have shot in 30 countries that are 220/50hz (even some that are 100/50hz, like the eastern half of Japan) and have never had a problem: Whenever I see any non incandescent source, fluorescents, neon, mercury or sodium vapour, I set my shutter to 1/100th.
If you set the shutter speed at multiples of 1/50 of a second, you will not have a problem. Most NTSC cameras do not have a 1/50th setting, so you must use 1/100th.
Similarly, if you shoot a PAL camera in the US or other 60hz country, set the shutter to 1/60th. All PAL cameras have this capability.