Part of the consortium that was the only bidder to deliver the Government’s National Broadband Plan (NBP) has pulled out of the tendering process.
It is understood that SSE is withdrawing from the consortium with Enet, who were the final bidders for the tender after Eir withdrew from the process earlier this year.
In a statement, chairman of the Enet consortium David McCourt said while he could not comment on the NBP process, the consortium is "considering and reviewing structures" to ensure the "optimum response to the tender process".
He said he wanted to underline in the strongest possible terms Enet's "continued commitment to Ireland and to the Government's policy of delivering a high-speed rural broadband network".
Mr McCourt said the consortium has "always understood the criticality of the project to the State".
He added: "The process is on track, with our final bid submission due in the coming weeks. Thereafter, we expect the process to reach a successful conclusion in the near-term."
In a separate statement, SSE said: "We have nothing further to add beyond the statement of the consortium."
The NBP is a Government initiative to deliver high speed broadband services to all businesses and households in Ireland.
Published in 2012, the NBP committed to make high speed broadband available to more than half the population by 2015.
Since then various updates to the plan have been published.
Fianna Fáil spokesperson on communications Timmy Dooley said the plan as a whole is now under threat.
He said: "The viability of the National Broadband Plan is now under threat to such an extent that it is conceivable that no contract will be signed this side of 2020.
"As of yet, SSE has not outlined its reasons for pulling out but it's clear as night follows day that the process has to date been so convoluted and bureaucratic that every major commercial player has not felt comfortable continuing.
"Minister Naughten must confirm when he became aware of SSE decision, and what his plans are into the future?"
Irish Rural Link has condemned the decision by SSE. The group says it puts the plan in jeopardy.
"The future of the plan is once again up in the air. The bidding process was to be finalised by now and this this will no doubt cause further delays," it said in a statement.
The statement added: "High speed broadband is key to attracting jobs and people to rural areas and regions and IRL are aware of businesses in rural areas that are suffering as a result of the lack of broadband.
"If the Government are serious in developing the regions and rural areas, this matter must be dealt with urgency and an Emergency Cabinet meeting be held immediately."