Erica de Belin also told jurors her brother, who is her best friend, was "caring", "empathetic" and "generous".

She said her brother was a "walking enigma" and was "spiritual" in that he was a "100 kg rugby league player" who did yoga, meditates, and practices daily gratitude.

Ms de Belin, who gave evidence via video link from England, told the Wollongong District Court about a story of her brother helping an old woman with arthritis by mowing her lawn.

She also said de Belin would wait around her work so they could ride their bicycles home together to ensure she was safe.

"I think anybody who has spent any time with him knows how good a person he is," Ms de Belin said.

"Being a professional athlete is only small part of who he is.

"It has been an honour and privilege to see him become a father."

De Belin's lip was quivering during much of her evidence before he broke down and loud sniffles could be heard throughout the courtroom.

The NRL player, 29, and his friend Callan Sinclair are in the third week of their NSW District Court trial in Wollongong over allegations they jointly raped a then 19-year-old woman in a North Wollongong apartment.

They have pleaded not guilty to five charges of aggravated sexual assault and claim the sexual intercourse was consensual.

Brian Johnston, the former chief executive of de Belin's club St George Illawarra, told similar stories of the footballer who was always willing to welcome new players from complex backgrounds.

"Jack had a natural ability to relax people in his company," he said.

Mr Johnston said de Belin showed people warmth, compassion, and was always encouraging, "even if competing for a similar position".

He told the jury de Belin, who has been a Dragons player since 2011, had shown "loyalty" to the club and had represented the organisation at school, charitable, community and media events.

Mr Johnston said he never received any reports of misbehaviour or incidents apart from this case, and noted that in nine years of playing professional league de Belin had never been sent off the field.

"He is one of the role models within our organisation," he said.

The trial continues.

- with AAP