Shane Ross has been criticised for saying that there should be strict sentencing guidelines for judges for all crimes.
The Transport Minister told the Sunday Independent that inconsistencies in punishing drink drivers sends out a message that motorists might get off.
However concerns have been raised that hard and fast rules on sentencing could breach the constitutional provision on the separation of powers.
Former Fine Gael Justice Minister Nora Owen (pictured below) thinks Shane Ross should concentrate on his own portfolio.
She told him: "Get on your own bus. Get on your own Luas. Keep an eye on your own department; it's not exactly running smoothly.
"You do start to wonder - what is the obsession that Shane has with judges?
"There is judicial discretion in our legal system... To say we should write down exactly (what sentences people should get) - people will suffer (if we do that)."