Thousands of people are flocking to a policeman's house in India's remote Andaman Islands to pray in front of two portraits of Jesus Christ, which are said to have been "bleeding" for the past two weeks, police and witnesses said.

Eric Nathaniel, a police radio operator, found red fluid trickling down a portrait of Jesus in his house two weeks ago which he believed was blood.

"We lit candles and prayed all night and a little later the blood dried but it soon started trickling down from the hands and heart of another portrait in the house," Nathaniel told Reuters in the islands' capital Port Blair on Wednesday.

Officials said red paint used in the portraits could be melting in the extreme humidity, but islanders and priests were coming in boats from remote parts of the Andaman and Nicobar archipelago to pray.

"This is indeed a miracle and shows that Jesus was in pain because of our sins," said John Chrysostom, a priest at the Anglican Church of Port Blair.

One portrait was temporarily moved to the local bishop's house for public viewing after police found it difficult to control swelling crowds.