A hospital in Tokyo's Toshima Ward mixed up patients of the same last name who died last summer and sent the wrong corpse to one next of kin, a hospital official said Wednesday.

The error occurred at Tokyo Metropolitan Otsuka Hospital due to a mistake by a company commissioned to return the corpses to their families.

"We deeply regret this incident, which should never have happened," said Masafumi Yoshino, a senior official at the hospital.

According to the hospital, two elderly men with the same family name died around the same time in July, and their bodies were taken to the morgue in the basement.

The company failed to confirm their identities and sent the body of the wrong man to a funeral hall. On being informed of the mistake by the family, who noticed the mistake when the body was about to be placed in the coffin, company staff went back to the hospital and returned to the funeral hall with the right corpse.

There are four freezing units in the hospital morgue, and the company is obliged to label the bodies with the full name, sex and the ward in which the patient had been treated. However, in the case in question, the firm had forgotten to label one of the corpses, the hospital said.