The SA Liberal Party has confirmed a breach involving some personal information of about 2,000 members.
The incident has been reported to police, with the addresses and phone numbers of members accessed without authorisation.
Through a statement, state director Alex May said no financial details were accessed.
She said affected members had been contacted directly but the party had received advice that the accessing of contact details was unlikely to create a risk of serious harm.
An email sent to members by the party president and director said a number of membership lists were accessed.
"The Liberal Party (SA Division) recently received a number of seemingly routine requests for certain membership lists," the email read.
"These requests were subsequently determined to be fraudulently undertaken, involving the electronic impersonation of Liberal Party office bearers entitled to receive membership lists under our constitution.
"Details such as your name, physical address, email address and phone numbers were released as part of this activity.
"As a party we take these matters seriously and have reported the matter to the relevant authorities, including police, and have sought external advice."
SA Police said the breach was reported to them on Tuesday.
"Eastern District Criminal Investigation Branch have recently commenced an investigation into deception offences, which involves the alleged release of details of members of a political party," SA Police said in a statement.
Police asked anyone with information to contact Crime Stoppers on 1800 333 000.
