A four-year-old girl who died from severe injuries after being forced to ride a 50kg motorbike despite repeatedly crashing lived in squalor and surrounded by drugs, a coronial inquest has heard.

Chloe Valentine, from Adelaide, died in January 2012 from injuries sustained over a three-day period in the backyard of a home at Ingle Farm.

The inquest, which began on Monday, heard that Families SA received more than 20 notifications from friends, neighbours and community workers between 2007 and 2011 about Chloe's mother, Ashlee Polkinghorne.

Concerns were raised about a house crawling with bugs and being full of rubbish bags and drug paraphernalia.

One of Polkinghorne's friends had even raised concerns about the woman's behaviour before she gave birth to Chloe.

The forensic pathologist who performed the autopsy on Chloe, Karen Heath, told the inquest the bruising the girl suffered was the worst she had seen on a child.

Polkinghorne and her former partner, Benjamin McPartland, are serving jail sentences for manslaughter through criminal neglect and will be eligible for parole in 2018.

The inquest is expected to continue for the next two weeks.