That's the promise from the president of the NSW board Dr Clive Lucas.

"It won't be allowed to go to wrack and ruin," the conservation architect told the Daily Liberal.

"The house means a great deal to me personally and is a significant site, not only for NSW but for all of Australia."

Dr Lucas described recent community upset about the temporary closure of Dundullimal as "unfortunate".

The house museum was to be shut from July 1 to October 1 "to address financial issues".

"A new way of operating the property will be developed because the old business plan has not been working," Dr Lucas said.

"The house will be properly cared for during the winter closure and some maintenance work will be done."

Dr Lucas said Dundullimal was a "beautifully romantic, wonderful sort of place".

"I still remember the first time I saw the property in the 1970s when I was visiting Dubbo in my capacity as the chairman of the National Trust historic building committee," he said.

"In those days we went out on searching tours to find buildings that the Trust needed to put on their list.

"We had visited a number of locations earlier in the day and some we had taken an interest in.

"It was very late in the afternoon when an old derelict place was suggested.

"It was almost twilight when I first saw Dundullimal. I could barely make out the shape of the building but I saw enough to know it was fantastic.

"I got up at dawn the next morning and headed out with National Trust photographer Jim Whitelock.

"Cattle had been walking through the house which had been used as a sort of a shed. Part of the roof had blown off and it hadn't been occupied since the 1950s when a gigantic flood had gone through the property.

"Despite all the defects, the house was magnificent in the dawn light. I still say Dundullimal is the most wonderful slab house surviving in Australia."

The property was one of the original squatting runs taken up in the Dubbo district.

The homestead was built by John Maughan in the 1840s as the head station of a 6,500 grazing holding.

A man of wealth, Maughan had been a merchant trading between India, Dutch Batavia and Australia.

He arrived in the colony in 1828 bring a large amount of capital, trading stock and two Indian servants.

Maughan took up residence in George Street, Sydney, where he had five servants, including three assigned convicts.

Accustomed to style, Maughan was keen to make a statement with his country homestead.

He commissioned a T-shaped slab building with internal plaster, a bell pull system to call servants, glazed French doors, tapered verandah columns, cedar windows and stylish chimney pieces.

The homestead featured a tennis court, orchard and outstanding garden.

Dr Lucas said Dundullimal had been a focal point for social activities in its heyday.

He wanted to see "the lovely old house" repaired and loved again.

Dr Lucas convinced the Trust to list the house and lobbied for grant funding to restore the property.

The house and a parcel of land were given to the Trust by the Palmer family.

When bicentennial funding was secured Dr Lucas was given the task of "putting Dundullimal back together again".

"It could not have happened without the wonderful work of builder Garry Waller," Dr Lucas said.

"He did a tremendous job. In my opinion Dundullimal is one of the most wonderful houses in the world.

"I have restored a great many historic places in my career but Dundullimal remains a favourite."