The Taoiseach today called on the Greens to put up or shut up about allegations on the business practices of Minister of State Frank Fahey.
Greens leader Trevor Sargent used Dáil privilege to allege the Galway West TD avoided tax and called on Bertie Ahern to sack him.
Mr Ahern suggested Mr Sargent should refer the allegations to the Standards in Public Office Commission (Sipo) or else withdraw them.
During leader's questions, the Greens leader asked: "What message do you send out to people, Taoiseach, when you have a minister like Frank Fahey, who is able to avoid tax in building up a multi-million euro property empire?"
As Ceann Comhairle Dr Rory O'Hanlon tried to intervene, Mr Sargent continued: "I'm asking about Fianna Fáil supporters, whether they be in Government or outside Government, and if the behaviour of those individuals is something that you're endorsing or standing over or recommending for others to emulate."
Amid protests from the Government benches, the Dublin North TD added: "Twenty properties in Ireland, Minister Fahey, and seven abroad, no recollection of receiving donations from Monarch Properties, a hair dressing business in Moscow.
"I would like to ask the Taoiseach if he is standing over the minister in his own Government who is under investigation by the Ombudsman for giving 75 per cent of total state fisheries compensation to two constituents?"
As the Ceann Comhairle tried to rule the questions out of order, Mr Sargent asked: "Under your watch, Taoiseach, fortune favours the corrupt and the greedy. Are you going to sack Minister Fahey?"
Mr Ahern reiterated in his reply that the Government has ended several tax incentive schemes in the biggest overhaul of the system since the early 1960s.
The country's top earners now paid more tax than they ever did, he added.
But Mr Sargent continued: "Is he going to stand idly by while dodgy builders in the Galway tent like Mick and Tom Bailey and dodgy builders in Government like Minister Frank Fahey set the real standards in Government under this Fianna Fáil/PD Government.
"Is he going to sack Frank Fahey. Is he happy with the standards being set in Government by his minister?"
Mr Ahern replied: "Whether there are dodgy builders or legitimate builders, it is because of the laws brought in that we have now stopped them evading taxes in the past and they are now paying large sums of money.
The Taoiseach said the current Government had worked hard to introduce legislation under the Standards in Public Office Bill.
He added: "Some members in this House think it is unduly strict. There is a system for investigating members. I am not the investigator on these issues.
"I have to say to Deputy Sargent, this day, you either put up or shut up. If you have facts, give them to Sipo [the Standards in Public Office Commission]. If you haven't, come in here tomorrow and withdraw them."