ONE of two staff who allegedly sexually assaulted female residents at a Central Coast nursing home was 18 years old and had only recently begun working there, raising questions about the supervision of junior staff at the facility.

Police yesterday confirmed that detectives from Brisbane Water local area command were investigating two former staff of the Peninsula Village home at Umina over two alleged sexual assaults and that the staff, both men, were aged 18 and 39.

Nursing home sources said the 18-year-old had recently begun working at the home as a nurse's assistant.

The incidents allegedly involved one resident, who suffers dementia, having her nightie lifted and her breasts handled, and another resident allegedly being vaginally assaulted this month.

Both men have been sacked. The Herald understands that two nursing managers have been suspended since news of the alleged sexual assaults broke.

The Nurses Association of NSW says assistant nurses should be under the supervision of a registered nurse while they are providing care.

"If personal care is being delivered, a registered nurse should be mindful of what is going on," said the assistant general secretary of the association, Judith Kiejda.

Lillian Jeter, of the Elder Abuse Prevention Association, said the situation at the Peninsula Village nursing home raised the issue of the need for laws specifying minimum staffing levels for aged-care facilities.

"Proper supervision and training of junior staff is one way of preventing abusive or neglectful behaviour, but nursing homes have to have a full complement of staff for this to happen," Ms Jeter said.

"There is no clear delineation about how many staff are actually required to operate an aged-care facility.That's why there are short cuts and a lack of supervision. Those who want to commit these acts of abuse are more likely to be able to do that when there is not a full compliment of staff with people who are able to supervise them."

Aged Care Standards auditors are reviewing the home.