A seven-year-old Perth girl who saved her baby sister from a dog attack in an extraordinary act of bravery says she is feeling "a bit better" after spending two nights in hospital.

Ella Andrews told 6PR Afternoon's Lisa Barnes she was with her stepmother and her 18-month-old sister at Piara Waters Football Pavillion on Monday night when she went with a group of children to play on a nearby playground.

Ella recovering in hospital.

"I was at the park and my step-mum and our friend's mum went to see the footy people, " she said.

"So I started to walk over to [my friend], and then I looked up.