Tammy Innes, 27, and her de facto partner Stuart Dewitte, 28, pleaded guilty in Melbourne County Court to a combined six charges including false imprisonment, aggravated burglary, assault and theft.

Prosecutor Holly Baxter said the couple "terrorised" the victim for over an hour before leaving with his iPhone, iPad, two credit cards, a Dyson vacuum cleaner, about $280 in cash, along with a threat from Dewitte that they would nail him to the ground and burn his house down if the victim called the police.

Innes' lawyer Graeme Davis said his client had taken an "enormous" amount of ice when she forced her way into the man's Kirkstall home on March 29, 2019, because she claimed she was traumatised by his conduct towards her as a child.

The court did not hear any evidence about any conduct the victim may have engaged in.

Mr Davis said Innes had a "dreadful upbringing" that led to psychological disorders, including Post Traumatic Stress Disorder and features of borderline personality disorder.

He said while that did not justify the "very, very bad example of false imprisonment", it did reduce her moral culpability to some extent.

Lawyer Raj Bhattacharya, representing Dewitte, said his client's own childhood trauma led him to "losing it" at the Kirkstall property and assaulting and terrorising the victim.

Clinical and forensic psychologist Jeffrey Cummins told the court Dewitte suffered Post Traumatic Stress Disorder following abuse he suffered as a child.

He said Dewitte's trauma-related symptoms could have triggered the offending.

But Judge David Sexton said it was a "significant leap" to be triggered and then act the way Dewitte did.

"It's extreme behaviour to get a nail gun, threaten to nail the victim to the floor, falsely imprison him and essentially terrorise this man for a significant period of time," he said.

"Many people that have suffered child abuse don't go around acting like this."

Mr Cummins said methamphetamine was also relevant to the offending, stating Dewitte had admitted to being both a regular user and under the influence at the time the offences were committed.

He said ice would have played a "significant role in the magnitude of that violence".

Both lawyers said Dewitte and Innes had spent over 12 months in custody - an experience they found difficult.

The court heard Dewitte was traumatised after a prisoner transportation van he was a passenger in caught fire, and that the couple had limited contact with their children while in custody due to coronavirus restrictions.

The judge said he would have to "carefully weigh up the matters".

He said he was "not overly attracted" to the lawyers' primary submission regarding their clients' moral culpability.

"I keep coming back to the gravity of the offending," Judge Sexton said.

"Quite frankly the offending is shocking, it is extremely serious... it is on the upper-end for range of (seriousness) of aggravated burglary and false imprisonment and that is the problem."

Dewitte and Innes will be sentenced on October 9.

They remain in custody on remand.

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