The party’s justice spokesman, Dara Calleary, said Mr Shatter was “only too happy” to invoke the doctrine of separation of powers when it suited him and ignore it when it didn’t.
Mr Calleary was responding after the minister’s row with the judiciary over pay cuts escalated.
The Government is moving ahead with plans to hold a referendum in October which, if passed, would allow the coalition to cut judicial pay.
But the judges have argued that, to protect judicial independence, the scale of any pay cuts should be determined by an independent body rather than the Government.
Their memo to Government on the issue was published late last week on the website of the courts service, www.courts.ie.
This prompted a terse response from Mr Shatter, who confirmed he had requested an official in his department to “inform the chief executive of the courts service that I did not believe this posting to be appropriate.
“I believe that this event, which was not sanctioned by anyone associated with the Government, is most unfortunate and it remains my hope that corrective action will be taken.”
But a legal source has since confirmed that the Attorney General, Maire Whelan, consented to the memo being posted on the website.
Mr Calleary said the minister should have been aware of the fact that the Attorney General was consulted.
“For the minister to continue to criticise judges saying that the use of the courts service website was ‘not sanctioned by anyone associated with Government’ can only be described as arrogant, if not somewhat sinister,” Mr Calleary said.
“You can’t on the one hand allow information to be released, only to censor or limit the way in which this is done.
“The justice minister certainly should have been aware that the Attorney General was consulted on the publishing of the memo. If not, perhaps there are deeper problems in Government.”
Mr Calleary said it was clear that the minister was “bent on asserting his power” over the judiciary.
“(Mr Shatter) called on judges ‘to show due respect for the role of Government and parliament’. Yet he has shown no such consideration when it comes to responding to the legitimate point that the level of reduction in judges’ pay should be decided by an independent source.”
Meanwhile, a courts service spokesman said the main purpose of posting the memo to the website was to make it available to the public and in particular the media, which had been seeking copies of it.
The spokesman said Mr Shatter’s department had been informed of this when it rang the courts service to complain on Friday.
It was made clear to the department at that stage that the memo would remain on the website until early this week for informational purposes.
The memo will be taken down from the site and archived at close of business today, the spokesman added.