The world's last male northern white rhino has died, the Kenyan conservancy taking care of it said, leaving only two females of its subspecies alive in the world.

Ol Pejeta Conservancy said in a statement it had made the decision with wildlife officials and his previous carers to euthanise on Monday the 45-year-old rhino, named Sudan, due to the rapid deterioration in his condition.

Sudan was being treated for age-related complications that had affected his muscles and bones and also gave him extensive skin wounds.

The rhino had spent two weeks in late February and early March lying in his pen due to discomfort from a deep wound on his right hind leg.

"His condition worsened significantly in the last 24 hours; he was unable to stand up and was suffering a great deal," Ol Pejeta said. "The veterinary team from the Dver Kralove Zoo, Ol Pejeta and Kenya Wildlife Service made the decision to euthanise him."