The former detainees claim to have been improperly locked up for periods ranging from a matter of hours to more than a year.

The 13 civil cases have been launched in the past seven years, seeking compensation under the Human Rights Act or damages under common law from the ACT government. A Canberra lawyer who represents such cases says many more claims could be made once former inmates become aware of their rights.

The individuals claim a range of errors were behind their illegitimate detention, including alleged mistakes made by the Sentence Administration Board as it dealt with breaches of parole and periodic detention orders.

Others allege they were detained due to irregular practices of the court registry, while some claim mistakes were made by sentencing courts.

Not all of the claims have yet made it to court, and only one case involving three detainees has been awarded damages, which totalled $200,000.

That case, finalised in 2009, involved three detainees originally sentenced to weekend detention by the courts but who were later ordered by the ACT Sentence Administration Board into full-time custody in the tough NSW prison system after each breached a periodic detention order.

But in each case the board either made invalid orders, failed to properly investigate why the breaches occurred, or failed to afford the trio procedural fairness.

It was found to have arbitrarily detained the trio and breached their rights as enshrined in the ACT's Human Rights Act. One of the prisoners, a serial drink driver, was mistakenly sent to Goulburn maximum security prison for 72 days.

The drink driver was strip searched by guards, robbed and intimidated by other inmates during his time at the facility, a period that was described as ''very unpleasant'' by the ACT Supreme Court judge presiding over the compensation case. The other two were detained for 20 and 29 days.

None of the other wrongful imprisonment cases have yet settled, although roughly half have identified undisclosed amounts of compensation they are seeking from the government.

Sam Tierney, of Ken Cush and Associates, has represented several ACT residents for alleged unlawful imprisonments, including alleged breaches of the Human Rights Act.

Mr Tierney said there were likely to be many more wrongfully detained inmates who had never taken action because they were not aware of their rights or because of their personal circumstances.

''The right to individual liberty is one of the most important rights in a free democratic society,'' Mr Tierney said. ''The ACT courts have been called on to consider the extent of the legislature's power in that regard.

''Fortunately, in the ACT additional protection is provided by way of the Human Rights Act. However, it's important that individuals continue to maintain a watchful eye on any encroachment by government or law enforcement authorities to this fundamental right.''

Acting Attorney-General Katy Gallagher said cases of unlawful imprisonment were uncommon, and the law had "long provided for compensation to those who are

imprisoned without lawful authority". Ms Gallagher said none of the claims had involved any malicious or deliberate conduct by authorities, and said cases would often turn on an interpretation of a particular law, and as such be "unavoidable".

"The fact that only a handful of claims have been made over the last five years, several of which remain unresolved and in which the territory has denied liability, demonstrates that the territory's processes are largely sound," she said.

Aulich Civil Law, a Canberra-based firm, said it had received several inquiries in relation to litigation in the area.

Principal Ben Aulich said the statistics alleging wrongful imprisonment were ''alarming''.

"A person's liberty is sacrosanct,'' he said. ''When it is wrongfully infringed, people should be compensated."