In a large bowl, cream together the butter, white sugar and brown sugar. Beat in the eggs one at a time then stir in the vanilla.
Combine the flour, baking powder, bicarb soda and salt; stir into the creamed mixture until just blended. Finally, mix in the chocolate chips. Shape dough into golf ball sized balls and place them 8cm apart into ungreased baking trays. Flatten slightly.
Bake for 8 to 10 minutes in the preheated oven. Allow biscuits to cool on baking tray for 5 minutes before removing to a wire rack to cool completely.