William Tyrrell's biological parents hid him from authorities for six weeks because they did not want him to be placed into foster care, an inquest into his disappearance has heard.

Key points: William's biological mother accused the Coroner of identifying her in court

William's biological mother accused the Coroner of identifying her in court She said she hid William for six weeks because she could not bring herself to give him up

She said she hid William for six weeks because she could not bring herself to give him up His father said he was the one who decided to keep the child from authorities

The court heard how Tyrrell's parents were in a "troubled relationship" with a history of substance abuse and domestic violence when he was born on June 26, 2011.

Nine months later, the Department of Family and Community Services received a court order to place the boy into care, but his parents hid him for six weeks at his paternal grandfather's house in western Sydney.

His mother — who cannot be named for legal reasons — was questioned about why she hid the child.

"I couldn't bring myself to give them my son," the mother said.

"What were your plans?" Counsel Assisting Tracey Stevens asked.

"We weren't really thinking ahead," the mother said.

The woman grabbed a tissue box and wiped away tears throughout the hearing, telling the court she was "very angry and upset" when she was told William was missing on September 12, 2014.

In her police statement, which was read to the court, the mother said she had nothing to do with the boy's disappearance.

"I definitely don't know where William is, I didn't take him," her police statement said.

She raised her voice when Deputy State Coroner Harriet Grahame reminded the court about suppression and non-publication orders.

"You made my name public!" she yelled.

"I never made your name public," Deputy State Coroner Grahame replied.

"I'll lose it!" the mother shouted.

William was hidden at his paternal grandfather's house for six weeks when he was nine months old. ( Supplied: NSW Police )

Tyrell's father, who attended every day of the inquest, said he was the one who decided to keep his son from the Department of Family and Community Services in February, 2012.

"I was the number one person that didn't want to give him to authorities … I was the culprit," the man said.

"At the time, I was upset, I was angry — it was a fabrication of bullshit — that's how I felt [and] I am sorry for that," he said.

On the day the boy in the Spider-Man suit went missing, the father told the court he remembered seeing police come into his home and speaking to William's biological mother.

"I was standing in the backyard having a cigarette [and] I heard the door banging. I said 'Who's that?'. She [the mother] said 'The police'," he recalled.

"What did the police tell you?" Counsel Assisting asked.

"I said, 'What's wrong?' [to the mother]. She said 'He's missing'," he said.

"I said 'He's f**king what?!' … that was my initial reaction."

The inquest will reopen in August.