Downing Street has defended the home secretary over his criticism of the jail term given to a man who abducted and sexually assaulted a girl of three.
The judge acted in accordance with guidelines in sentencing Sweeney
John Reid described Craig Sweeney's five year sentence as "unduly lenient".
Attorney General Lord Goldsmith is said to be unhappy and insisted he will not bow to political pressure when deciding whether to appeal against the sentence.
Tony Blair's spokesman said it was right for the home secretary "to articulate the concern the public has".
The spokesman rejected suggestions that Mr Reid may have jeopardised any appeal to increase Sweeney's sentence through his intervention.
He said Mr Blair would not comment on any individual case but would often express his determination to re-balance the judicial system in favour of victims of crime.
The Sentencing Guidelines Council is already carrying out a review of the amount of "discount" sex offenders should receive on their sentences for pleading guilty.
The attorney general's spokesman said: "The attorney has called for the file in Craig Sweeney's case in order to consider whether to refer the sentence to the Court of Appeal as unduly lenient.
"The attorney will make a decision purely on the merits of the case and not in response to political or public pressure. Calling for the file in no way implies that there will be a reference by the attorney. Still less does it imply any criticism of the sentencing judge."
Commons Leader Jack Straw also defended Mr Reid saying it was "perfectly appropriate" for the home secretary to intervene.
A Home Office spokesman had earlier said Mr Reid "is concerned that the tariff Craig Sweeney has been given does not reflect the seriousness of this crime and is writing to the attorney general to ask him to consider referring the sentence to the Court of Appeal as unduly lenient".
But Nick Clegg, the Liberal Democrats' home affairs spokesman, said it was "rank hypocrisy for John Reid to blame judges for sentences which are a direct consequence of recent legislation introduced by this government".
Lord Morris of Aberavon QC, attorney general in the late 1990s, said he would have been "extremely annoyed" by Mr Reid's intervention.
Ex-High Court judge Sir Oliver Popplewell said: "I think it's unwise for the home secretary to poke his nose into legal affairs."
However, relatives of the victim welcomed Mr Reid's intervention and called on the government and judiciary to ensure such crimes were "properly punished".
However, Judge John Griffith Williams QC was acting in accordance with guidelines in sentencing Sweeney, 24, at Cardiff Crown Court.
The judge gave a notional sentence of 18 years, but this is halved to reach the actual sentence. He was then obliged to cut a third off in view of the guilty plea.
Sweeney - who was known to the family - had snatched the girl from her home after she had returned home from a shopping trip and while her mother made a telephone call.
He drove her to his Newport flat where he was living after being released early from a three-year sentence for indecently assaulting a girl aged six. There she was sexually assaulted.
She was only found by police hours later in Wiltshire, after a car chase prompted by Sweeney having no lights on his car and jumping red lights.
He drove erratically at speeds of up to 100mph with the girl in the car.
Earlier this month, five judges at the Court of Appeal increased the minimum jail sentence on Alan Webster, convicted of raping a 12-week-old baby, after the case was referred to them by the attorney general.