Damp plaster behind shower tiles

[Sean Smith]

Hi im after some advise my upstairs shower has begun to leak so ive decided to revamp the whole thing. While taking off the tiles ive noticed that the plaster is damp and stained. im looking at fitting a new shower and tiles will i have to remove that section of the wall and hang new plaster board or can it be treated and tiled over.

thanks

[bs]