The mother who drove her 4 children into a lake felt 'dizzy' before the crash.

The mother-of-seven who drove a car into a suburban Melbourne lake on Wednesday says she felt dizzy before the crash.

Akon Guode, 35, reportedly told family members she felt “very dizzy” before the incident in Wyndham Vale, in Melbourne’s outer suburbs.

Three of the four children in the car — baby boy Bol, aged one, and Madit and Anger, both aged four– died when the 4WD plunged into Lake Gladman.

A five-year-old girl, Awel, remains in hospital in critical condition, ABC News reports.

Ms Guode was treated at the Royal Melbourne Hospital under police guard, but has since been discharged. She was released from custody on Thursday night after police questioning, but the homicide squad continues to investigate the incident.

The children’s adoptive told SBS Radio he believes the woman did not deliberately drive into the water.

“My message to the community – because there is a lot of talking around, there is untruths – what I can tell them is they have to wait for the report from the police investigation, that will be the truth,” he said. “What I believe is she can’t do that… because she loved the kids.”

Emergency services said the car plunged into the lake near the intersection of Manor Lakes Boulevard and Pedder Street at Wyndham Vale on Wednesday.

Police officers and passers by jumped into the lake and smashed holes through the car’s windows to rescue the people inside.

They then started giving the children CPR, ABC News reports.

Police confirmed one child died at the scene, while another passed away on the way to hospital about 5:30pm. The third died in hospital before 7:00 on Wednesday night.

Superintendent Stuart Bateson said on Wednesday it was unclear what caused the crash, and said it was too early to say if the woman driving the vehicle was the mother of the children.

He said that police were investigating a “tragic set of circumstances”.

“It’s going to be a really harrowing investigation,” he said.

“In circumstances like this, with such catastrophic consequences, we really need to have all the facts before we start talking about what we think might have happened,” Superintendent Bateson added on Thursday.

Locals — including members of the Sudanese community, have left toys, flowers and candles besides the site of the crash. Fairfax Media reports that the Sudanese community has also rallied around the children’s family, with a vigil starting at their Wyndham Vale home on Wednesday night.

The children’s family arrived in Australia from South Sudan in 2008, while the children’s biological father is believed to have died in Sudan, according to Fairfax Media.

Community members said Ms Guode, 35, came to Australia to escape war after his death, ABC News reports.

A candlelight vigil in memory of the lost children is planned for the weekend.