Finian McGrath, Catherine Murphy, Tony Gregory and Seamus Healy are to meet with a constitutional expert in the next few days on the issue and McGrath said that it was now "looking like a constitutional challenge".

Following advice from the attorney general, the government last week announced that it would not be changing the Dail constituencies.

The constitutionality of the current constituencies was first raised by theSunday Tribune, based on research by political analyst Odran Flynn.

The concerns raised were underlined by preliminary census figures, released in July, showing that due to massive population growth, a number of constituencies breached the constitution's requirement for equality of representation.

However, the government last week stated it can only have a review of the constituencies based on the final census figures, which will not be available until next year . . .

too late to change the boundaries in advance of a general election.

It is widely believed in legal and political circles that, following the publication of the preliminary figures, the constituencies are wide open to a legal challenge. The constitution makes no distinction between preliminary and final figures, and the CSO has indicated that there will be no difference between the preliminary and final population figures.

McGrath said he was "hopping mad" at the government's decision not to review the constituencies. "We are meeting with a constitutional lawyer next week and we will not accept this decision, " he said, adding that he and his fellow independent TDs would act "in the national interest".

Catherine Murphy, TD for Kildare North, stressed that the group of independent TDs would need to get advice and assess the prospects of success from the lawyer before collectively deciding whether to proceed, but added: "Clearly, I wouldn't go as far as to seek this opinion if I didn't have a legal challenge in mind".

Murphy said that none of the four TDs was in constituencies likely to be substantially changed by a boundary review.

"This a point of principle about the very basis of representative democracy. I think it adds to the argument that we are not personally affected, " she said.

Labour's environment spokesman Eamon Gilmore last week accused the government of making the decision not to change the constituencies on "political grounds". He called on the government to publish the legal advice it received from the attorney general. "There is no good reason why that advice cannot be published, " Gilmore said.

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