Australia is facing the possibility of a warmer and drier 2017, with weather forecasters saying the chances of an El Nino weather pattern are rising.

The Bureau of Meteorology says recent changes in the tropical Pacific Ocean and atmosphere, and climate model outlooks all suggest there is a 50 per cent chance of El Nino forming this year.

El Nino is associated with below average winter-spring rainfall over eastern Australia and warmer than average winter-spring maximum temperatures in southern states.