A Queensland couple has pleaded guilty to manslaughter over the death of an elderly relative they housed in a shipping container in freezing conditions in Tasmania.

Jassy Anglin, 53, and her 56-year-old husband Michael Anglin, were extradited from Cairns last year to face a charge of manslaughter over the death of Jassy Anglin's mother, 77-year-old Janet Mackozdi.

The Supreme Court in Hobart heard the woman died of hypothermia after spending one night in a shipping container on the Anglin's Mount Lloyd property in July 2010.

Crown prosecutor Darryl Coates told the court the couple had been caring for Ms Mackozdi after her health declined.

On the night before Ms Mazckodi's death, she had slept in the property's main four-room hut with the Anglin family.

The court heard on the night of her death, the couple had put Ms Mackozdi to bed in a shipping container adjacent to the hut, where two of their children also spent the night.

The court heard a temperature simulation report prepared by experts from the University of Tasmania estimated temperatures in the shipping container would have been between -1 degree celsius and 2.9 degrees on the night.

Mr Coates told the court when the couple realised Ms Mackozdi was dead the following morning, Jassy Anglin washed her mother and dressed her in a tracksuit, ugg boots, scarves and a jacket, before driving her to the New Norfolk hospital.

The court heard the couple told staff they had been on a family trip to Mount Field, and later had not been able to wake Ms Mackozdi.

Later, Jassy Anglin admitted to police her mother had in fact died in the shipping container.

Mr Coates said the Crown was not suggesting the pair had intended to harm Ms Mackozdi.

"Had they stopped and thought about it, like they should have, they would have known of the serious risk and consequences that would have occurred," he said.

"Placing her in a shipping container on such a freezing night when she couldn't fend for herself is a grave departure from community standards.

"However a relevant factor is that it was only for that one night, and they didn't realise she was suffering."

'A tragedy for everyone'

Sorry, this video has expired Queensland couple plead guilty to causing elderly lady's death ( Ellen Coulter )

Mr Coates told the court the case was a tragedy.

"A tragedy for the deceased, but I accept it's a tragedy for both accused," he said.

"They've lost their mother, their children have lost their grandmother and on top of that they're facing a serious charge."

Michael Anglin cried as the couple's lawyer, Tamara Jago, told the court Ms Mackozdi's death was the consequence of one episode of gross misjudgement.

Ms Jago said this was not a case of abuse.

She told the court the couple had been moving possessions into the Mount Lloyd property, and decided it would be preferable for Ms Mackozdi to sleep in the shipping container that night because of the possessions stacked precariously everywhere in the main residence.

"The idea was that it would be for one night only," she said.

Ms Jago told the court Jassy Anglin had dressed her mother in a beanie, socks and dressing gown, given her a blanket and doona and had a three-bar heater on in the container.

Ms Jago said Jassy Anglin felt the manner in which her mother died was degrading and humiliating, and her initial deception was a result of her shame.

"There was nothing sinister about the behaviour of either of the accused," Ms Jago said.

Ms Jago told Justice Shan Tennent a wholly suspended sentence would be appropriate.

The two were released on bail for sentencing in April.