ACT Liberal politicians have defended their use of voter-tracking software to record and share personal details of constituents who contact their offices.

Liberals MLA Alistair Coe recently contacted Katherine Beauchamp using her private, unlisted phone number.

When asked how he had the number, Mr Coe's office said it was logged in the party's "constituent engagement system" when Ms Beauchamp contacted ACT Liberal senator Gary Humphries about a separate issue last year.

Mr Coe's habit of using the system to send 18th and 21st birthday cards to constituents had also raised eyebrows among rival MLAs.

The admission provides a rare glimpse into the methods political parties adopt to profile voters, target advertising, conduct opinion polls, and devise policy.

The Labor Party runs a similar profiling database, called Electrac.

The practice has attracted the ire of privacy campaigners since voter-tracking software became common during the 1990s.

Political parties are exempt from privacy laws that limit organisations from collecting personal information.

Parties receive monthly copies of the electoral roll from the Australian Electoral Commission, which provides voters' details, including their name, age, gender and address.

The parties then augment this basic data with information collected while interacting with constituents.

The Canberra Liberals declined to divulge the type of detail logged against individuals, but said the database was an administrative tool.

"The system is really just an electronic filing system," a spokesman said.

"If a constituent contacts a member it is a paperless way to record the nature of the issue and generate a letter to a minister or other government contact, similar to a Microsoft access database.

"Like all matters dealt with by members and their staff, the greatest care is taken to assure people's privacy is protected unless the constituent indicates that they have or would prefer to have the information made public through the media."

ACT Labor branch state secretary Elias Hallaj said: "Just like any large organisation, we use an address list, in this case the electoral roll, to send out letters to our constituents."

Minor parties have similar, but less sophisticated databases due to fewer resources.

The ACT Greens said individual constituent information provided to their MLAs was kept confidential and not used for other purposes.

But Australian Privacy Foundation board member Nigel Waters, the federal deputy privacy commissioner from 1989 to 1997, said voter tracking software was a breach of privacy and could be misused for malicious purposes.

"We know from anecdotal evidence that there are all kinds of soft-intelligence on there, things like peoples likes and dislikes and whether they're considered cranks," Mr Waters said.

The Australian Law Reform Commission in 2008 recommended the removal of the exemption.

Mr Waters said the loophole had concerned the commission for two decades.

"It's completely outrageous that political parties have gotten away with this so long," Mr Waters said.

"It's complete hypocrisy that there are rules imposed on the rest of the population but they think they're above it all.

"One of the advantages of privacy laws is that you are entitled to ask what information organisations hold about you and you can go on to quiz them about where they got it from.

"But because political parties are exempt you can't even do that."

Ms Beauchamp said she was sickened her personal details had been added to the database without her consent.

She had requested her details deleted from the file.

"I am sickened at the betrayal of trust, in that information I was asked to give in order to get help from an elected representative's office was secretly funnelled to a secret file available to all political party colleagues for election and other party political purposes," Ms Beauchamp said.

"I am appalled that such files exist, that major parties throughout the Australian system use their legislative powers to allow them and that everyone else is subject to agreed-on privacy principles."