The 47-year-old man, known by pseudonym Charlie Colt, faced Sydney's Downing Centre District Court via video link on Monday and pleaded not guilty to sexual intercourse with a person under the age of 10 and indecent assault of a person under 16 between 2010 and 2012.

The court heard a 2012 police interview in which the complainant, now 14, said Colt took a "small, skinny stick" from a gun bag kept inside his tent and sexually assaulted her with it.

"I screamed really loud because it hurt," the then-six-year-old said in the video.

"He didn't say anything ... just laughed."

The girl, whose mother is Colt's biological sister, later told police said she couldn't remember the incident.

But in a further interview in 2019, the teenager said she was "embarrassed" to admit to the incident on a video that might be later played in front of a jury.

"I was embarrassed because there was going to be a jury - I didn't feel comfortable to admit it," she said.

Colt has never previously been convicted of a crime, the court heard.

The Colt clan came to prominence in the early 2010s after police uncovered about 40 members of the family living in an uninsulated shed, old caravans and tents on a NSW bush block.

A dozen children found on the property were placed into state care in 2013 by a children's court, which heard genetic evidence showed all but one of the children were the product of incest.

The trial without a jury continues before Judge Kate Traill on Tuesday.

Australian Associated Press