Rolleston Principal Corrections Officer Karl Bennett said most people, including the men involved, started off thinking knitting wasn't something that men do, particularly not male prisoners.
"When they have given it a go they have found it is more difficult to master than they thought. They have generally found it a very relaxing and rewarding pastime which they are keen to continue with.
"I'm sure the dogs and cats really appreciate it too."
Canterbury SPCA chief executive Barry Helem said over the last three months the number of dog and puppy welfare cases has increased by 50 per cent compared with the same period in 2014.
"With such a large number of animals requiring care over the cold winter months it is vital that we have enough supplies of bedding to help keep them warm and free from illness."
Mr Helem said the Canterbury SPCA received no government funding.
Costs totalled over $2 million a year and the shelter relied heavily upon the generosity of the community to maintain their service, he said.
"We simply cannot afford to purchase all the bedding we require and are grateful to Rolleston Prison for their efforts.
"As the need for our service continues to increase, this valuable support really will help us to 'save lives' over the winter months."
One of the prisoners involved in the knitting group said he was enjoying doing something meaningful for others in need.
"I find knitting for those in need very rewarding. Knitting quilts for sick little cats and dogs gives me a joy of giving back to society."
