An Aboriginal woman in Katherine has been breath-tested in her own home by Northern Territory Police — despite officers receiving no complaint about her — and arrested for being in breach of a domestic violence order.

Key points: A woman was charged with breaching a domestic violence order that mandated she was not to drink alcohol with her partner

A woman was charged with breaching a domestic violence order that mandated she was not to drink alcohol with her partner Police had not received a complaint before going to her house and breath-testing her

Police had not received a complaint before going to her house and breath-testing her The Katherine Local Court and Supreme Court each dismissed the case

The charge against the woman, Aileen Roy, was dismissed in Katherine's Local Court, but NT Police appealed the decision and pursued the case to the Supreme Court, where a judge also rejected it.

North Australian Aboriginal Justice Agency lawyer Beth Wild said the decision would have implications for others in the same position.

"The privacy that we have has to be balanced against police coming into our homes and conducting breath tests," she said.

"What we're seeing here is that people who are doing nothing else but being drunk are being hauled before the courts."

'The evidence was unlawfully obtained'

In April last year police launched Operation Haven, which targets domestic and family violence in Territory towns where alcohol abuse is rife.

The operation had recently been extended to Katherine, where police officers were conducting "pro-active DVO compliance checks".

Ms Roy had a domestic violence order out against her, a condition of which was that she wasn't to be in the company of her partner while she was drinking.

In the early afternoon, three police officers appeared at the door of the unit that she and her partner shared and told her they "wanted to conduct a domestic violence order check".

One of the constables said he thought if Ms Roy was drunk her partner, who suffered seizures, may be in danger.

Ms Roy stepped outside and blew a positive alcohol reading and was then taken to the watch house.

NT Police argued they had the powers to take someone to the watch house under domestic violence laws, but the Supreme Court Justice Dean Mildren disagreed.

"I find that the police had no power to go to Ms Roy's home and take a sniff of her breath and then require [her] to provide a sample of her breath, that they were trespassers when they entered her alcove and knocked on the door," he said in his decision.

"Consequentially, the evidence was unlawfully obtained."

In cross-examination the constable involved agreed that the police had received no complaint of a potential breach of the DVO.

NT Police said their "powers in relation to domestic violence have not changed and police will still be able to respond to reports of domestic violence committed at residences and enter the premises if deemed necessary under the legislation".

But Ms Wild said Operation Haven is already thoroughly carried out.

"Certainly these breaches are already very actively policed," she said.

"What this decision says is that police aren't able to come into our own homes to check whether or not people are intoxicated when they don't have any info about whether or not a domestic violence order has been breached."