Family Planning NSW has fallen victim to a data breach that may have exposed personal information on up to 8000 users of the agency's services.
The agency has informed clients that its website had been hacked last month, and databases containing information on 8000 clients have been accessed.
The attack is believed to have compromised a program being managed by online security company Adelphi Digital.
The information includes details of clients who have used Family Planning NSW's website over the past two and a half years, seeking appointments or advice about abortion, contraception and other services.
According to the disclosure, the hackers demanded a bitcoin ransom over ANZAC day in association with the hacked information as well as data stolen from other government websites.
The website and all web database information was secured at 10 am on the following day.
But the Family Planning NSW website is currently down due to a "security update" and will be brought back online after internal testing and an external security review. The agency's clinics are operating as usual.
There is currently no evidence that the compromised information has been used by cyber attackers, and more sensitive medical information remains secure, the agency said.