This is the dramatic moment three giant monitor lizards battled for dominance in a vicious clash that left one of the dinosaur-like creatures with a bloody gash on its neck.

Hemanth Kumar Tholappa, a regular visitor to Sungei Buloh Wetland Reserve in Singapore, was drawn to the sound of loud thrashing near the water by the Visitor Centre.

When he looked towards the lake, he saw the trio locked in what appeared to be a fierce territorial struggle.

Footage taken by Hemanth shows the Godzilla-like reptiles wrestling violently in the water, with one of them clearly displaying a deep wound across its neck on August 16.

He explained that the injury appeared to have been caused, or worsened, when the wounded creature struck metal beams beneath the adjoining platform while struggling during the fight.

The injured animal, which had previously been dominant, was suddenly outnumbered and eventually overpowered.

Hemanth later told local media: 'I almost thought it was going to drown, but then the animal recovered.

'The other two continued fighting after moving away from the wounded lizard.'

Despite the bloodshed, the clash did not appear to be a fight to the death.

Hemanth added: 'What I observed and learned from this experience at the reserve is that, in most cases, the lizards don't really harm one another.

'They may engage in multiple bouts before a winner is decided.'

He said the struggle lasted more than two hours - far longer than any wildlife encounter he had previously witnessed at the reserve.

When he spoke to a National Parks (NParks) volunteer about the encounter, the staff member admitted the spectacle was 'truly remarkable' and unlike anything they had seen before.