Chris Rickard, 49, sustained deep cuts to his abdomen and face after being attacked by the kangaroo as he tried to free his dog, which was being held underwater by the animal.

He said the kangaroo lashed out as he went to the dog's aid, cutting him above the eye.

He struggled to keep his balance in the water, fending off blows from the kangaroo and holding on to his dog with the other hand.

Mr Rickard responded with an elbow to the throat and the kangaroo backed off a little, allowing him to crawl to the bank with his dog.

"If I had not ducked it would have got me on the eye," Mr Rickard told Channel Ten.

He said that his blue heeler had been held under the water for about 20 seconds when he raced in to free it from the kangaroo's grip.

The kangaroo then lashed out at the dog's owner.

Advanced life-support paramedics were called to the property at 9.35am.

"The 49-year-old dived into the dam and managed to free his dog but he was injured in the process," paramedic Michael Vosbergen said. Mr Rickard was in a stable condition in the Austin Hospital last night.