Santoro resigns

Federal Minister for Ageing Santo Santoro has resigned from the Howard ministry after admitting he had not revealed all his share trading activity.

The Prime Minister, Mr Howard said in a statement the Senators actions were unacceptable.

"After a detailed review of his financial records, required by me, he provided advice indicating a number of investments not hitherto disclosed to the Senate or to me.

"He has written to the Registrar of Senators' Interests today providing the relevant information.

"While common sense needs to be applied to issues of ministerial conduct including the capacity to accept inadvertent error, circumstances such as those now outlined by him are unacceptable.

He told reporters this afternoon he had written to Prime Minister John Howard tendering his resignation.

The senator had failed to immediately sell off stocks in a biotechnology company after being appointed to his health-related portfolio in 2006.

The resignation has been part of a concerted battle between both sides of politics over ethics and ministerial standards.

Two weeks ago Senator Ian Campbell resigned as a Minister after revealing he had met inappropriately with former WA Premier, Bryan Burke.

Shadow Attorney General, Kelvin Thompson was also forced to resign after he gaver a reference to a Melbourne crime figure.

The Government has been pressing Labor Leader, Kevin Rudd, over the details of his meetings with Mr Burke.