The demolition proposal has already attracted strong opposition from the National Trust, as it campaigns to have more examples of significant architecture from the second half of the 20th Century preserved.

The application has been lodged by Warrawong firm Pecorp Design on behalf of the owners.

Pecorp's Frank Maounis said it was still early days in the assessment process, but after 45 years of being weathered in its seaside location, the house was no longer in good condition and was potentially affected by concrete cancer.

Shellharbour City Council says it is still assessing the application, although the house has been identified as being on a draft heritage register.

The house was believed to have been built in 1964, based on a project home design by Nino Sydney, a one-time chief architect with Lend Lease Homes, the National Trust's Graham Quint said.

In 12 years with Lend Lease, Mr Sydney designed about 60 project homes, with the Warilla house said to be a design called Safari.

"You can view this house from all directions and it looks fantastic," Mr Quint said.

"It's an extraordinary design."

Elevated concrete slab houses are rare and it was likely this was one of the more expensive homes of its day, Mr Quint said.

"It appears intact and sound, and the proposed demolition and its loss would not result in a better replacement built form, but the opposite."

Mr Quint said surviving buildings from a Georgian and Victorian era were valued because of their age, but more recent items were not yet as valued despite their merit.

"In time they are what we will want to keep, but at the moment they are disappearing very quickly."