Sixteen serious complaints over the treatment of residents in Queensland's state-run aged care homes were referred to the federal government for investigation last year.
But the state's health minister says the allegations at the government-run facilities were just a drop in the bucket compared to more than 4000 relating to the private sector.
Details of the complaints have come to light as the quality of Australia's aged care centres remains in focus at a royal commission being held this week in Brisbane.
One of the complaints at the state-run facilities alleges sexual assault by an employee, while another alleges excessive force by staff.
Queensland Health Minister Steven Miles says many of the investigations were still ongoing and would not name the facilities involved.
"Some of them are ongoing investigations and some of them are police investigations, so it's up to the appropriate authorities to determine when and how they are disclosed publicly," Dr Miles told ABC radio.
About half of the complaints were referred to police for investigation.
Queensland Health says it takes a "full disclosure approach" to reporting allegations of wrongdoing at its 16 residential aged care facilities, which look after more than 1000 elderly people across the state.
The private sector manages about 460 aged care centres which look after about 39,000 people across the state.
Queensland opposition leader Deb Frecklington accused the government of "covering up" the allegations of abuse because they were revealed through a Right to Information request made by the ABC.
"It is sickening that vulnerable old people have been physically and sexually abused in state-run facilities that are meant to care for them," Ms Frecklington said.
Australian Associated Press