Minister of State for Housing and Planning Jan O'Sullivan has said she intends to implement the recommendations of the Mahon and Flood tribunals to ensure that the planning system is changed.

Speaking on RTE's Prime Time programme Minister O'Sullivan said she would introduce legislation in the autumn which will include provision for a planning regulator.

She said the regulator will be in a position to carry out investigations and assessments of forward planning.

The Minister was speaking following the collapse of the corruption trial involving businessman, Jim Kennedy, and three former councillors following medical difficulties affecting chief State witness, Frank Dunlop.

Mr Kennedy and three councillors - Liam Cosgrave, then with Fine Gael; and Colm McGrath and Tony Fox who were Fianna Fáil representatives at the time - denied allegations of corruption concerning the rezoning of land in Dublin during the 1990s.

Former councillor Don Lydon, who also denied a charge of corruption, was discharged on Monday.

Minister O'Sullivan said she couldn't comment on the court case itself but there was a great deal of evidence in the Flood and Mahon tribunals.

She said she had already directed three local authorities in the past year to reverse bad planning decisions and would do so again if required.

Minister O'Sullivan said she was serious about ensuring that planning is incorruptible in the future, and has already taken action to de-zone the equivalent of 500,000 new houses which would otherwise become ghost estates.