A disability support group refused to act on allegations that an employee sexually assaulted a 12-year-old girl in his care because it feared losing funding, a royal commission has heard.

The alleged victim's mother, Maree Welch, wept as she told the public inquiry about her daughter Bobbie​, who she described as a "delightful young woman" with a severe genetic condition.

The girl was abused at age 12, the commission has heard. Credit:John Donegan

Mrs Welch told the Royal Commission into Institutional Responses to Child Sexual Abuse Bobbie was allegedly sexually assaulted by Family Support Group Australia disability support worker John O'Connor​ in 1995. Mr O'Connor has consistently denied the allegation.

The inquiry into disability groups heard Mr O'Connor allegedly sexually assaulted Bobbie at his home on the Gold Coast.