The Taoiseach has told the Dáil that it is not possible to order the downward revision of commercial rents.
Mr Cowen said advice from the Attorney General indicated that it was not constitutionally valid for the government to interfere with private contracts.
He was responding to Labour leader Eamon Gilmore, who called on the Government to back his party's motion calling for a removal of the provision for upward only rent reviews on commercial leases.
Mr Gilmore said he had legal advice to suggest that it was possible to reverse the upward only rent culture. He called on the Taoiseach to publish the Attorney General's legal advice. He accused the Taoiseach of 'wrapping himself in the Constitution' to protect landlords.
The Taoiseach said the Labour motion could be considered if it were legally possible.
Legislation banning the upwards only rent review clause in all future leases came into force earlier this year, but it applies only to new leases, and many businesses will not benefit from it.