The Delhi zoo Bengal tiger was unwell and veterinarians were treating it (Representational)

A Delhi zookeeper who didn't withdraw his hand quick enough after keeping a bowl of water inside the cage of an unwell Bengal tiger has lost his finger. The eight-year-old tiger didn't eat the finger though, a zoo official said.

The worker Fateh Singh, 45, was rushed to Ram Manohar Lohia Hospital in central Delhi, where doctors tried to reattach the broken middle finger of his right hand. But they had to cancel the procedure as the damage was severe, the Hindustan Timesreported. Mr Singh also suffered a fracture on the thumb.

"The doctors from the surgery and orthopaedics department considered rejoining the finger, but on further examination found that there was too little bone left to do so," the newspaper quoted a doctor at the hospital as saying. The zookeeper received a few stitches.

Delhi zoo curator Riyaz Khan said the Bengal tiger was unwell and veterinarians from Bareilly and the zoo Director Renu Singh had examined the big cat on Monday night.

"The late night inspection may have rattled the tiger. Such incidents have happened in the past too," Mr Khan said, according to news agency PTI.

The Bengal tiger, which the zoo has given a name, Rama, was brought from Mysuru in 2014. "It is unwell since July 27 and has not been eating enough. It was only on August 14 that an inspection was conducted by the Delhi zoo veterinary officer," another zoo official said, asking not to be identified.

The animal was kept in a 'squeeze cage' to give easy and safe access for the veterinarians. But the frequent checks may have agitated the tiger, the official said.

A 'squeeze cage' has a movable panel that can be adjusted to restrict an animal's movement, usually for vaccination and medical check-up. "The animal is in pain," the official said.

Dehi zoo has seen animal attacks in the past. In September 2014, a white tiger attacked and killed a 20-year-old man who fell into its enclosure.

The Bengal tiger is found primarily in India with smaller populations in Bangladesh, Nepal, Bhutan, China and Myanmar. It is the most numerous of all tiger subspecies with more than 2,500 left in the wild, according to the World Wide Fund for Nature.