The house-warming packages were received by people who had reported their relatives' deaths and asked for their mail to be forwarded to them.
A Swiss Post spokeswoman told AFP a new computer system was at the root of the mistake.
"Unfortunately, some data handling errors occurred and led to these isolated regrettable cases. We immediately took measures to avoid similar cases in the future," the postal service said in an email.
It said it had apologised to the families involved.
"It's hurtful," said a caller to a local radio programme who received a package for her recently deceased father along with a pamphlet welcoming him to his new residence.