Another child has died following a tragic shed fire in a family home backyard

A third child caught in a horrific shed fire in the family backyard has now died, as a fourth fights for her life.

A third sibling has died following a shed fire in the backyard of their family home in Victoria last weekend.

Four-year-old Isaac McGregor died from horrific injuries at Melbourne’s Royal Children’s Hospital on Wednesday.

His younger brother Saige McGregor, three, and sister Ashylnn McGregor, 18 months, died at the scene.

Older sibling Mavis, six, is still fighting for life.

“(She) remains in hospital in a critical condition,” Victoria Police said.

Corio fire victims Mavis, Saige, Ashlynn and Isaac McGregor. Picture: Supplied

A GoFundMe page has so far raised more than $55,000.

“Isaac sadly grew his wings and reunited with his baby brother and sister,” an update on the page read on Wednesday.

“He will always be remembered as the heroic young boy who gave his life trying to protect his siblings.

“We thank everyone so much from the bottom of our hearts for all the donations and support.

“This community is absolutely incredible.”

The shed went up in flames. Picture: NCA NewsWire / David Crosling

The four children were playing in a backyard shed at their Corio home, southwest of Melbourne, when it went up in flames on Sunday morning.

Their mother Jasmine frantically tried to rescue them after a couch caught fire and trapped them inside.

She was able to pull them from the burning shed, then neighbours helped her call emergency services.

The children’s mother managed to pull them out of the shed. Picture: Andrew Henshaw

The children’s father Kane McGregor expressed his anguish in a social media post on Monday.

“Worst 36 hours of my life. Absolutely broken-hearted having to let go of my two youngest babies,” he said.

“Only thing keeping me together is holding onto and fighting for my other two.

“Come on Mavis and Isaac, you are both so strong and way too stubborn to give in so keep fighting the winning fight.

“RIP Wiggles and Saigey. I love you two so much.”