The West Australian Government is fighting a court decision to award a couple more than $1 million after they were tasered and unlawfully detained by police, leaving them with physical and psychological damages.

Law professor Robert Cunningham and his wife Catherine Atoms have been waiting more than nine years for someone to take responsibility for their unlawful tasering.

An internal police investigation cleared the officers, the Corruption and Crime Commission has refused to reopen an investigation into the police, and on Tuesday a matter of law threatened to thwart their bid for more than $1.1 million in damages.

In the latest chapter of their fight for justice, they sat in the WA Supreme Court of Appeal to watch the WA Government argue it should not have to pay them damages because of a legal technicality.

This legal argument appeared at odds with the assurance given to the ABC in March by the WA Attorney-General, John Quigley, that the couple will receive a damages payment.

The Government's lawyer, George Tannin, argued the state is not liable for damages under the Police Act when police had behaved maliciously.

But Martin Cuerden, acting for Dr Cunningham and Ms Atoms, argued the state should pay the damages because District Court judge Felicity Davis found it had concurrent liability with the police.

The state is appealing the 2016 decision of Justice Davis, who awarded the couple the damages after finding the officers had fabricated evidence, abused their powers and falsely imprisoned, assaulted and tasered the couple.

But the three officers — Glenn Caldwell, Peter Clark and Simon Traynor — claimed they could not pay their costs because they had little or no money.

Catherine Atoms and Robert Cunningham were awarded more than $1 million in damages for false imprisonment and assault. ( ABC News: Manny Tesconi )

The Police Act also gives the Treasurer discretion to pay the damages if the couple is unlikely to receive them.

But in court today, Justice Michael Buss said the act did not include an obligation by the Treasurer to pay the full amount, noting they "may pay the claimant all or some of the damages and costs".

The legislation also says any payment by the Treasurer would be considered a debt, suggesting the police officers would have to pay it back.

A spokeswoman for the Attorney-General said the appeal was "an important question of law which, in the state's view, ought to be determined by the Court of Appeal."

"The state appealed on the basis that the District Court was incorrect in holding that the state was jointly and severally liable for the malicious acts of the police officer defendants," she said.

The case was heard by three judges — Justice Buss, Justice Janine Pritchard and Justice Graeme Murphy — who reserved their decision.

Dr Cunningham and Ms Atoms declined to comment.