Which type of liner are you using?

Dick, if the rocks are placed on a scrap piece of liner to protect the actual pond liner you should be okay.
A piece of flat field-stone put down first onto the scrap pad of liner and the rock(s) placed onto that will help spread the weight about a bit.
I have rocks of various sizes and weights, sitting on the shelves of my ponds and there has been no problem with them piercing the liner.
"Horton"

i have lots of river rocks around my pond on the shelfs . i have not had a problem yet with them piericing the liner and i walk on them. but i made sure that they all were flat with no sharp edges to cut into the liner.

Horton's idea sounds great using the old liner as a pad.

good luck with your new pond. laura

thanks much for the advice. the pond is beautiful!!