I don't think this will work for long. I actually start my puppies (newborn/whelping) in a pack N play with a plastic under-the-bed type rubbermade container in one end, lined with soft blanket for a whelping box. The rest is covered with pee pads and has water and food for momma. Once the puppies are ready to climb out of the whelping box I move them to a playyard that has 3 times the room. They get a soft bed and the play yard is lined with pee pads. They stay in this arrangement until they are ready to go to new homes.
This is also what I put up for Annie my new pup that I just got at 11 1/2 weeks old. The pack N play is too easy for them to snag their little nails in the netting. It also becomes too easy for them to climb and possibly hurt themself during an escape attempt. They may also try to chew theirselves out. So -- I would not recommend a Pack N Play for puppies old enough to rehome.
This is what I recommend you get :
http://www.walmart.com/ip/North-Stat...t-Gate/8457890 These are so convenient and can be used for a very long time. They are super easy to clean and last virtually forever.