Strongly criticising the government's failure to comment on the High Court challenge, Murphy said she and McGrath, along with their legal advisers, would "consider all options" if the government failed to address their concerns that 11 D�il constituencies are in clear breach of the constitution.

Asked if this could include taking an injunction to stop the election being called, Murphy said they would hold off deciding whether or not an injunction is appropriate, until "we talk thoroughly with our legal advisers".

The pressure on the government on this issue increased yesterday with Green Party leader Trevor Sargent warning his party would consider taking legal action after the election if party candidates narrowly missed out on a seat in the affected constituencies.

Focusing on Dublin North and Dublin West - the two constituencies most under-represented based on the latest census figures - Sargent said:

"If Green Party candidates in the coming election, such as Roderic O'Gorman in Dublin West or Councillor Joe Corr in Dublin North, were to narrowly miss out on winning a D�il seat, they would be directly affected, both as citizens and as public representatives, by the government's failure to revise the constituency boundaries. Supported by the Green Party, they will consider taking legal action."

He accused the government of failing to act on the preliminary population figures, released last July, "for reasons of political expediency", but also criticised Fine Gael, saying, "We have heard very little from representatives from Fianna F�il, the PDs and Fine Gael."

Catherine Murphy yesterday said she believed there was still time for the government to amend the constituencies before the election which, she noted, did not have to be held until July. "The government is relying on a situation where they think only a judge can stop the election and that a judge won't do that because of the whole issue of separation of powers. I think that's the way they're thinking and it really shows a huge amount of arrogance on their part."

The independent TDs' solicitor Eddie McGarr last week wrote, on their behalf, to the chief state solicitor emphasising the "urgent need for action by the government to remedy the situation" and ensure the impending election is "fair and beyond constitutional challenge".

Murphy said Trevor Sargent's warning was "a sign of what's to come unless this is addressed".

However, environment minister Dick Roche yesterday told the Sunday Tribune that legal precedent down the years, and the advice of the attorney general, "made it clear that the only way to proceed was on the basis of the final census figures". He added that as soon as the census figures for each electoral division were available on 26 April, he would begin the process of establishing a boundary commission "to report back within six months".