If there are so many holes that you have to fill before you can reupholster, the professional conservators of old furniture often use Bencon Epoxy Wood:
I use sawdust the same colour as the wood when filling in holes, rub it in with my finger till the hole/s are full then a drop of thin superglue. I have salvaged many an old woodworm eaten chair with this method even when large area's are just like paper and woodworm dust.
Thanks for the replies it is for an old chair that the wife is re- upholstering so many tack holes obtained over many years. looks like it has been shot with a 12 bore shotgun.
I will try a paste and glue method on a small area first
Again many thanks
Richard