A four-year-old cat called Bonny has survived after being walled in beneath a bathtub in Germany for seven weeks, its owner said.

"It's a miracle," 60-year-old widow Monika Hoppert said. "I'm a strong believer, I think she must have had a guardian angel. I'm so happy."

Bonny disappeared on June 19 while workmen were replacing pipes in the block of flats where Ms Hoppert lives.

The black cat was last seen in a neighbouring apartment, where the cladding around a bathtub had been removed.

Just before the tub was sealed up again, Bonny had probably crept underneath, Ms Hoppert said.

By the time the neighbour heard Bonny's plaintive miaowing from behind the tiles on August 8, the cat's weight had dropped from six kilograms to two kilograms.

"I couldn't believe it. But when I got down there, I knew it was my cat because they all have their own voice," Ms Hoppert said.

Bonny was so weak the vet recommended she be put down.

But Ms Hoppert nursed her back to health with watered down kitten food.

"She's almost back to normal now. This morning was the first time she'd jumped onto my bed again," she said.

- Reuters