Don't just block them, make some money off of them -
Have your host install Mod Geo IP if it isn't already and grab Max Mind's IP database, even their free one is decent:
http://www.maxmind.com/app/mod_geoip (some hosts will already have a database installed)
Then, simply add this to your .htaccess file:
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} ^CN$ [NC,OR]
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} ^HK$ [NC,OR]
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} ^MO$ [NC,OR]
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} ^MY$ [NC,OR]
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} ^SG$ [NC,OR]
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} ^TW$ [NC]
RewriteRule ^(.*)$
http://www.chinese.url [R,L]
Signup for
Jade Bucks and send them there (recommended), an aggressive dialer or even a toolbar sponsor that pays for shit installs like
Loud Cash.