Utzon spent eight years working on the Opera House but left the job in 1966, disgusted with money-saving changes made to his visionary masterpiece.

He vowed never to return but has now accepted an offer to oversee interior renovations, according to the Sydney Morning Herald.

But 81-year-old Utzon, who has never visited his building, is not expected to return to Sydney for the project.

Sydney Opera House took 16 years to build

Instead, Australian architects will travel to his home on the Spanish island of Majorca to consult with him on the redesign.

National president of the Royal Australian Institute of Architects, Nigel Shaw, welcomed Utzon's appointment in the Herald saying it will see the building's original design fully realised.

The Sydney Opera House, which celebrated its 25th anniversary last year, cost A$100m (�42m) in lottery revenue when construction started in 1959.

But the project went so seriously over budget that work was suspended and when Utzon left, the local council finished the job.

So much money had been spent on the outside of the building that there was comparatively little left for the inside, which led to complaints that the job was inadequate.

Members of the Sydney Symphony Orchestra recently threatened to boycott the concert hall because they claimed the building's acoustics were not doing justice to their music.

Last month another dispute between Australian state and federal governments stopped an application being forwarded to have the landmark World Heritage Listed.

The Herald said Utzon had written to New South Wales state prime minister Bob Carr, saying he had spent "eight wonderful years" working on the building.