Yes, you can use any plug-pack as long as the plug-size and the output voltage/amps are the same (or higher, for the amps). Most of the ones that come with cordless phones seem to be single voltage (110 OR 220V, not both).

When I moved from Australia to the US I found it was cheaper to buy a new cheap Uniden phone and use it's plugpack with my existing phone than it was to buy a plugpack...