Peter Jones, Otto's owner, has had the dog, which now suffers arthritis, since he was a puppy.
Mr Jones, 68, said his wife Lynn, 55, have a certificate to prove his age and Guinness World Records are now investigating.
Mr Jones, a retired sales manager, said: "When I saw this dog had died and he was the oldest in the world, I thought Otto must be getting on to being the oldest as well. I thought it would be good to see if Otto is the oldest. My vet said to me that they hadn't got any older dogs going to see them.
"He will follow me wherever I go and doesn't go running off. I if go out, I come back and he's sat by the door waiting. He's still going strong and he used to run like a greyhound and was really fast. But in the last couple of year's that has stopped, what do you expect when he is 147?
"He's got a bit of arthritis but apart from that he's quite well."
The greatest age recorded for a dog is 29 years and five months for an Australian cattle-dog named Bluey, owned by Les Hall of Rochester, Victoria, Australia. Bluey was obtained as a puppy in 1910 and worked among cattle and sheep for nearly 20 years before being put to sleep on November 14, 1939.
A spokesman for Guinness World Records said: "It sounds like Otto could be the new top dog. Sadly the oldest living dog, a dachshund names Chanel, passed away at the end of last month, she was 21.
"We would welcome Otto's owners to contact us if they believe that he may now be the world's oldest living dog.We can then provide them with the evidence that we will need to see to verify the claim."