A family violence survivor who was raped and bashed repeatedly by her partner says she heard police laughing with her attacker after she called them for help, the Royal Commission into Family Violence has heard.

The woman was the first victim to give evidence at the royal commission, which began on Monday in Melbourne.

The mother of four, who asked not to be identified for her own safety, told the commission she was repeatedly abused by her husband, who was controlling and kept the telephone in a padlocked room.

She told the inquiry he refused to let her talk to people because he told her she was supposed to be looking after the house, not talking all day.

The woman said her husband would force her and their four children to sleep in the car parked outside his work when he worked nightshifts.

She said when she finally decided to call the police to report the abuse, she heard police laughing while they were interviewing her husband.

The inquiry heard the woman's husband told her: "All I have to do is tell them 'You understand women, they're irrational, they overreact sometimes'."

"It just made me feel so much more isolated, so small in my own home," she said.

The woman told the commission she and her four children were homeless for a year, living in a tent when it was warm and in their car when it was cold.

She said her children always attended school.

The witness broke down when telling of trouble she had finding crisis accommodation in Melbourne's northern suburbs, saying she was told she could only pick two of her children to stay with her.

"I explained I had four children and I was offered the chance to pick which two of my children stay with me," she said.

Earlier, the commission heard one in six Australian women had been subjected to partner violence since the age of 15.

For men the ratio is one in 20.

In extreme cases the violence results in death.

The commission was told one study found each year in Australia there were on average 115 family violence-related deaths.

In Victoria in 2013 there were 44 deaths linked to family violence.

The public hearing will go for 20 days over the next month.

The commission is expected to hand down its findings in February next year.