A dog rescued from a floating roof in the sea off Japan's northeast coast more than three weeks after the tsunami has been reunited with her owner.

Wagging her tail, the two-year-old mixed-breed dog named Ban jumped into her owner's arms Monday at an animal shelter in the Miyagi prefecture in northern Japan.

Toshio Suzuki, who runs the shelter, said the owner's name will not be released for privacy reasons. The only details provided about the owner are that she is a woman, she has an adult daughter and the family suffered tsunami damage — although officials were not specific.

The reunion came about after the owner saw her dog's rescue on television on Friday.

The dog was found floating on a roof about two kilometres off the coast of Kesennuma. After multiple attempts, the Japanese coast guard eventually retrieved the emaciated dog.

It's believed she had been adrift since the March 11 tsunami that devastated the country.

Public broadcaster NHK broadcast images of the reunion, with the woman hugging Ban and the dog warmly wagging her tail.

Suzuki said the shelter currently houses 19 dogs and several cats separated from their owners after the disaster.