The cost of pursuing David Eastman for the alleged murder of Colin Winchester is nearing $30 million, according to figures provided by ACT authorities.
The most recent ACT budget in June set aside $7.4 million for the retrial of the 71-year-old, who will be charged again with the murder of Mr Winchester in 1989, who was then assistant police commissioner. That comes on top of more than $20 million in previous budgets and other costs that have not been separated from earlier budgets.
Mr Eastman spent 19 years in prison before his original conviction was quashed in 2014, when he was released. He will now be retried, with the trial set down for six months from February.
The 2017-18 budget set aside $2.4 million for the courts, $2.3 million for the director of public prosecutions, $1.9 million for legal aid and $800,000 for ACT police to handle the retrial.
Asked for the historic costs of Eastman's trials, appeals and inquiries, a Justice and Community Safety Directorate spokesperson said from 1992 to 2002 the costs were met within the budget. Between the 2001 and 2004 budgets, an extra $1.5 million was provided.
After that costs were met within existing budgets until 2012.
Since 2012-13, $26.3 million had been set aside for Eastman matters, including the Martin inquiry.
In 1995, Mr Eastman was found guilty of shooting Mr Winchester and sentenced to life imprisonment. His 1997 appeal to the High Court was dismissed in 2000, but he continued challenging his conviction with ongoing cases until 2007, when he was finally refused leave to appeal.
But in 2011, an application for an inquiry into his conviction was successful, and the inquiry was ordered in 2012. The Martin inquiry found in 2014 that he did not get a fair trial called for Eastman's conviction to be quashed. As a result, the Supreme Court quashed Mr Eastman's conviction in August 2014, but ordered a retrial. He has been free on bail since then.
The Justice and Community Safety Directorate said about $1.5 million set aside in the 2016-17 budget for the retrial had not been spent.
"The separation of powers, the presumption of innocence and the right of legal review are all vital safeguards in our legal system," the spokesperson said.
"It is important we respect the judicial process as it continues."