No, they have different meanings. If you “put off” something it means you are procrastinating, that you are avoiding doing something and intend to do it at a later time. You can also be "put off" something. This means you no longer like something. For example: He was put off eating chocolate when he found out how fattening it was.
“Push off” has two meanings I can think of. One is if you want to tell someone to go away you can say “push off”. The other meaning is to physically push away from something such as to push a boat away from a jetty or to push away from the end of a pool when swimming.
Hope this answer isn't too confusing :-)