Angela Marshall, a high-end interior decorator with Melbourne design firm Adelaide Bragg & Associates, lived in the prime minister's official Canberra residence during her father's government and is a councillor of the Australiana Fund, the body responsible for managing historical art and furniture for official Australian government residences.

During questioning in Senate Estimates on Monday, Department of Prime Minister and Cabinet deputy secretary Elizabeth Kelly said Ms Marshall was awarded the $9900 contract to create a furniture layout for the newly refurbished home as the long-running $11.61 million million renovations came to an end.

Ms Kelly said she was introduced to Ms Marshall by Prime Minister Malcolm Turnbull's wife, Lucy Turnbull, who accompanied her to a storage facility in Hume to inspect items of furniture stored for the house since the 1980s.

Ms Kelly initially said she had "directly sourced" Ms Marshall for the work herself after discussions with Mrs Turnbull, but later said she needed to take on notice questions about who in the department had given final approval. Government tender rules require competitive processes for procurement.

"Angela Fraser had lived in the house when Malcolm Fraser was prime minister," Ms Kelly told the hearing.

"It was on the basis of expertise and on the requirement to do the work quickly," she said. Mrs Turnbull had recommended Ms Marshall as "someone who could assist" with the project at short notice.

Ms Marshall was contacted for comment on Monday.

Before joining the Hawthorn-based firm, she worked for 12 years with Sydney designers Cameron Kimber and has experience in "concept and resolution of high quality residential design and decoration".

Earlier this month Mr Turnbull ordered a $45,000 independent review into blow-outs in the renovation project by Braddon-based management consultancy Projects Assured.

The costs of heritage refurbishment and security upgrades had originally been expected to cost about $3.2 million, but after significant further works were ordered by former prime minister Tony Abbott the costs grew from $9 million to nearly $12 million.

The audit came after 42 variations to the main contract in three years. It is expected to be handed to Mr Turnbull by the end of the month, but the government has not committed to releasing it publicly.

Labor senators Penny Wong and Jenny McAllister have asked the department for a detailed breakdown of the costs of household items purchased for the 1927 home. The hearing was told about $100,000 was spent on a new "luggage lift" for inside the house, and original bespoke furniture had been reupholstered at a cost of between $4000 and $11,000.

A full audit of items in storage units at Hume and Queanbeyan is under way. Ms Kelly said they included arm-chairs, various sofas and items designed by the home's first decorator Ruth Lane Poole.

Ms Kelly defended the new lift and said a staff member had recently sprained her ankle on the "precarious" main hallway stairs.

"We have a number of staff that work in the house and the luggage lift is to avoid the need to take suitcases and heavy items up and down the staircase," Ms Kelly said.

Moving the Turnbulls' personal items from their Sydney home and private Kingston apartment in January cost taxpayers a modest $1980.