A Victorian mother tried desperately to save her four children from a horrifying shed fire that claimed two of their young lives on Sunday, it has emerged.

Ashlynn McGregor, 18 months, and three-year-old Saige McGregor died when the blaze broke out at the Corio property, on the outskirts of Geelong, on Sunday.

Their older siblings Mavis McGregor, 6, and Isaac McGregor, 5, remained in a critical condition in the Royal Children’s Hospital on Monday.

Emergency services were called to the blaze just after 10.30am on Sunday. Ashlynn and Saige died at the scene, while Mavis and Isaac were flown to hospital in Melbourne.

All four children were inside the shed when a couch was set alight. Their mother, 26-year-old Jasmine Beck, was inside the home at the time and ran to the shed, trying desperately to rescue them.

The children’s aunt and uncle, Sarah Guardiano and Anthony McGregore, said Beck ran into the shed after the couch caught fire.

“She had to move a couch that was on fire to pull the kids out,” Guardiano said on Monday.

“Jasmine did her very best.

“Pulling all those babies out, like you can imagine, you know, having to call the fire brigade, having to put out a fire, having to pull out your children. She did the best she could to get them all out as quickly as she did.”

Beck, who burned her hands in her efforts, was at the bedsides of her two surviving children on Monday.

McGregor described his nieces and nephews as “loving and boisterous”.

“Ashlynn is like the love of my life,” he said.

“Mavis and Isaac were the first two kids that ever taught me how to love properly.

“They’re the babies of our family, the youngest members of our family, and they’re gone.

“That’s how we want everyone to remember them.”

A GoFundMe page has been set up for the children’s grieving family.

“This family will never be the same without these children in their lives,” organiser Daina Leech wrote.

“I’m hoping to help this family ease the financial cost of laying those beautiful babies to rest, as this is such an unimaginable situation for any parent to go through.”

Leech wrote that the children’s family had been told that Mavis and Issac “have a long road of recovery ahead, with multiple surgeries still needing to happen”.

“The medical treatment these children will require, if they pull through this, will be life-long,” she wrote.

Police Inspector Emma Bartel said there was chaos at the Corio property when emergency services arrived. The circumstances of how the fire started were unclear, although it was not being treated as suspicious.

“There is a lot that we don’t know at this stage,” she said on Monday.

“We have spoken to a family and we have spoken to neighbours. We are trying to piece together the events of what has taken place.”

Police had spoken to the children’s mother but she wasn’t in a position to provide further details, Bartel said.

Arson detectives are investigating, with police desperate to provide answers for the family and community.

Bartel said neighbours tried to come to the rescue of the four children before emergency workers arrived.

“It’s a very close-knit community here,” she said.

“There is some long-term relationships among the neighbourhood here.

“There is a lot of this community rallying together for the sake of the … families that are involved.”

Bartel said it would take time for detectives to get to the bottom of the tragedy.

“It is unfortunately the worse-case scenario of what we could expect with an incident like this,” she said.

A report will be prepared for the coroner.

-with AAP