Remember to add the weight of adhesive and grout to the tile weight (about 6kg but depends on how thick a bed you use).
The weight limits are 28kg for skim and set plaster, 20kg for skimmed plasterboard and 32kg for un-skimmed plasterboard - all assuming that they are firmly fixed to the wall.
So if you mean normal plastered walls you may be a little over but whether it's okay or not will probably be more affected by what condition the plaster is in. If it's old then it will have lost adhesion to the wall and need replacing. If it's new and well bonded you may be okay.
The weight limits are 28kg for skim and set plaster, 20kg for skimmed plasterboard and 32kg for un-skimmed plasterboard - all assuming that they are firmly fixed to the wall.
So if you mean normal plastered walls you may be a little over but whether it's okay or not will probably be more affected by what condition the plaster is in. If it's old then it will have lost adhesion to the wall and need replacing. If it's new and well bonded you may be okay.