Non-native English to teach English in China

Hello,

I have heard that it is very difficult for a non-native English speaker to obtain a Z visa to teach English in China. I was wondering is it actually true? Some of my friends from Russia and Kyrgyzstan are working in China (teaching English) without a Z type.

Please advice is there is a chance to receive a Z type to teach English in China if I am not native English speaker.
Thank you.