The exhibition in an eastern Swiss castle was due to be opened to the public on the sidelines of a company meeting by Axpo, a Swiss electricity group that also runs three nuclear power stations.

Hundertwasser, who died in 2000 at the age of 72, was an opponent of nuclear energy.

Axpo said in a statement that the Swiss art expert organising the exhibition had been told that his "livelihood would be endangered" over the weekend.

"He also received threats that the exhibition would have been disrupted by all means," the statement added.

Axpo did not give details of the threats or say who they came from.

The organisers said they feared that visitors would also been at risk. Several private collectors and museums had withdrawn works, according to Axpo.

A foundation set up by Hundertwasser, which says it has the moral rights over his work, said in Austria that it had not been consulted about the project and had opposed it.

"We only became aware of the presence of this sponsor when our partner submitted the proofs of the catalogue for this exhibition, that is, at the last moment," said Andrea Fuerst, a spokesowman for the Foundation.

"We cannot tolerate that the name of Hundertwasser, who was always engaged against nuclear energy, should be associated with a company that runs nuclear power stations. It's a violation of his memory and his image," Fuerst said.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.