It was the drone shot that got everyone talking - and questioning - on social media.

Sydney Morning Herald photographer Nick Moir has come to the defence of his photo that caused controversy online, explaining why he couldn't save the animals stuck in mud at Lake Cawndilla near Menindee.

The drone shot accompanied a report on the effects of extreme heat and continuing drought on wildlife, following on from the horrific mass fish kill on the Darling River Credit:Nick Moir

Some people had questioned why photographs were taken, but the animals were not rescued. Moir said he tried to help - but simply couldn't.

"I took the shot with a drone about a kilometre and a half away from the lake bed," Moir said. "People forget if the roo got stuck in the soft mud, it wouldn't have been so great for me either."