Southern Australia is in the midst of a climate tug-of-war that's giving Melbourne weather previously experienced in NSW Riverina towns such as Deniliquin, according to new CSIRO research.

Warming global temperatures tend to push westerly winds south while El Nino weather patterns tend to push them north.

Fog shrouds the Maribyrnong River with Melbourne temperatures plunging yesterday to 2.3 degrees overnight. Credit:Jason South

The atmospheric tussle of the past 50 years is becoming one-sided as global warming wins out, as inland dry zones shift about 250 kilometres south, said Wenju Cai, a principal research scientist and climate modeller at the CSIRO.

''The greenhouse-gas induced climate change is so strong that it overcomes the pulling towards the equator caused by El Nino,'' Dr Cai said, referring to the weather pattern involving cooler sea-surface temperatures in the western Pacific often associated with dry spells over eastern Australia.