An Adelaide magistrate has questioned how children under the supervision of South Australia's Department for Child Protection were left to live in squalor with their father.

The father was sentenced in the Port Adelaide Magistrates Court over the "rancid" and "putrid" living conditions at his Housing Trust home where his children stayed.

He pleaded guilty on Monday, on the first day of his trial, to two counts of failing to provide suitable accommodation for his son and daughter in Adelaide's western suburbs in March 2015.

The court heard the children had been in and out of foster care from a young age but had been reunited with their biological father under the ongoing supervision of the department, then known as Families SA.

The squalor included piles of beer and pizza boxes. ( Courts Administration Authority )

When police responded to a domestic disturbance at the father's address in March 2015, they discovered the filthy living conditions and removed the children.

The squalid conditions included faeces, dead cockroaches and piles of rubbish around the home. Photos tendered to the court showed beer and pizza boxes, as well as a filthy toilet and kitchen.

The children's father told police he had been assaulted by his neighbours and the ongoing conflict with them left him too scared to go outside and take the rubbish out, so it piled up.

Magistrate Kym Millard questioned how that situation was allowed to go unnoticed for months when the children were supposed to be under the protection of the department.

"How did it come about that the children were allowed to live in this squalor?" he asked.

"I think it would not be surprising if the vast majority of people in the community held the view or expressed the view 'how can this happen?'"

'Unfortunate' that department had to be notified

The court heard the father often took his children to live at his mother's house but when it was too crowded there he would take them back to his own house.

It heard child protection workers did not check on the children at his house.

"To suggest that contact at the home address did not take place suggests there's been an unfortunate potential for this situation to have been allowed to develop and occur," Mr Millard said.

He said it was unfortunate it took a phone call to police to prompt attention.

"It's unfortunate that it took that type of event to lead to the state of the house coming to the attention of the relevant public authority, in this case not only police but more particularly the senior practitioners of the department."

Mr Millard said the father "clearly had problems" that led to him effectively becoming housebound and likely needed significant assistance himself.

The magistrate questioned how authorities could remain unaware of the situation. ( Courts Administration Authority )

The man's defence lawyer, Adam Richards, told the court his client loved his children and they were not neglected in other ways.

"Whatever else can be said about him and whatever one can say about the standard of the house and cleanliness and other matters, it doesn't mean he doesn't love his kids," Mr Richards said.

"He loves his kids dearly."

The father was placed on an 18-month good behaviour bond.