The Moriarty Tribunal now looks set to continue into 2011, its 14th year of operation, following last week's extraordinary intervention by a central figure in the competition to award the second mobile phone licence to Esat Digifone.

A hard-hitting statement from Michael Andersen, a consultant to the government in the licence competition, has effectively put paid to the expectation that the hugely expensive tribunal can complete its work before the summer.

It has also raised further question marks about the modus operandi of the beleaguered tribunal and prompted renewed speculation about the likelihood of further legal challenges to Moriarty, the state's longest running public inquiry ever.

Last month, Judge Michael Moriarty admitted that he had made "two significant errors" in his inquiry. In his statement, Andersen bluntly accused the tribunal legal team of bias and claimed that the Tribunal had made "a large number of factual inaccuracies that I have corrected previously [without success]", in its preliminary findings.

Andersen had decided he was not willing to provide further assistance to the tribunal because of what he claimed was its "hostile and inappropriate treatment". But his signalling last week that he is willing to come to Dublin Castle and give evidence means that he will inevitably be called as a witness.

And his evidence – certain, based on his statement, to be strongly critical of the tribunal's preliminary findings – is likely to lead to pressure to recall other witnesses, including the civil servants involved in running the competition.

The new evidence is also likely to result in Judge Moriarty having to release to affected parties a third round of provisional findings. Experienced tribunal watchers say that this will bring the inquiry up to the end of this year and beyond.

Former communications minister Michael Lowry this weekend said that the "motivation, management and cost of the tribunal must now be seriously questioned by the Oireachtas".

He claimed the tribunal's credibility was "in tatters" and that it was now "glaringly obvious there was unpardonable bias against myself and others".

Based on figures just released, the fees of the four key tribunal legal team figures is continuing to cost the state an average of €200,000 a month, suggesting a price tag of around €2.4m for 2010. However, this figure does not include the third-party legal costs that the tribunal is continuing to rack up.

Although the provisional findings of the tribunal are confidential, businessman Denis O'Brien is on the record as saying that those findings had said the licence was issued illegally to his company, Esat Digifone.

The preliminary findings are also known to deal extensively with the actual competition process. It has been widely reported that the findings were sharply critical of more than 12 civil servants and their handling of the competition. However, Andersen's statement – and likely evidence – will raise fresh question marks about those findings also.