"The minister's decision was to extend his letter of resignation at his initiative," Mr Rudd said.

"I accepted that resignation, it was the right thing to do."

Mr Rudd described Mr Fitzgibbon as a "first-class Defence Minister".

"The Government expects high standards of accountability on the part of ministers," he said.

"I feel very sad about this," Mr Rudd told a press conference in Canberra....

Mr Rudd said Mr Fitzgibbon had made "mistakes in terms of accountability and paid a high price".

He said Mr Fitzgibbon's resignation goes to the "probability of the process engaged in".