A group campaigning against the Lisbon Treaty has made a formal complaint to the State's ethical watchdog alleging "illegal use" of taxpayers' money by the Government.
Libertas wrote to the Standards in Public Office Commission (Sipo) requesting that it launch an immediate investigation into a website set up by the Department of Foreign Affairs to provide information on the treaty.
In a statement today , Libertas said website is "blatantly political in nature, and as a result is a misappropriation of taxpayer funds in support of a political campaign being undertaken by the main Government party".
Libertas's executive director Naoise Nunn claims the www.reformtreaty.ie
website breaches the ruling of the Supreme Court in the Patricia McKenna case from 1995.
That judgment restrained the use of public funds for the purposes of promoting a particular side in a referendum debate.
Libertas is also considering initiating a legal challenge against the website in the High Court on the basis of the McKenna judgment.
A spokesman said a decision on legal action would be taken in two or three weeks.
The Department of Foreign Affairs rejected the claims and said the website contained comprehensive information about the Lisbon Treaty, including the full text of the treaty document.
No date has been set for the referendum but there is speculation that Taoiseach Bertie Ahern favours a date in May.
Minister for European Affairs Dick Roche today rejected claims by Libertas that the Lisbon Treaty would result in a loss of sovereignty for Ireland within the EU.
Speaking on RTÉ radio in a debate on the issue with Naoise Nunn of Libertas, Mr Roche urged the public to read the official information in relation to the Lisbon Treaty for themselves.
He said the EU could only exercise powers that were conferred on it by the member states.