A letter dated June 13 and signed by the company's managing director Peter Thurlow, says that "construction on all projects has now ceased" because the company has "fallen victim to the harsh times" and "recently entered voluntary administration".

But the federal regulator, the Australian Securities and Investments Commission, says it has no record of Excellence Homes (trading as Excellence Developments) or related companies going into administration.

The company operates offices at Thornton, East Maitland and Broadmeadow and its website was still active yesterday, promising to deliver "peace of mind" to people choosing to use it as a builder.

Wallsend accountant Vincent Heufel said one of his clients, building a 17-unit development at Cardiff, was facing a cost increase of at least $300,000 as he shopped around for a new builder.

Mr Heufel said Excellence was assuring customers that home owners' warranty insurance would cover their jobs but this would not be the case until the company went into administration.

"While the company still stands there will be a valid and binding contract holding the customer to the builder," Mr Heufel said.

The June 13 letter from Excellence Developments says there is "no one simple reason behind the demise of the Excellence brand".

Mr Thurlow said his former employees would work with two new investors to establish a new building company, Regal Developments (Aust) Pty Ltd, which was "gaining the necessary statutory documentation including a builder's licence and home owner's warranty insurance".

This company would take over the stalled Excellence projects.

Excellence has declined over the past fortnight to respond to Herald requests for information.