Michael McKevitt intends to appeal his conviction for directing terrorism and membership of the Real IRA, his wife confirmed this afternoon.
Issuing a statement outside Portlaoise Prison where her husband will be held, Ms Bernadette Sands McKevitt criticised the non-jury Special Criminal Court describing the verdict as a "political decision".
"My husband has refuted those allegations and will continue to refute those allegations and he intends to take this further," she said.
"The court case that took place was nothing more than a show trial."
She said the evidence put to the court was constructed and that her husband was the victim of a "stitch-up".
Earlier Mr McKevitt had sent a message from his jail cell saying he intended to appeal the verdict. And outside Portlaoise Prison his wife intimated she may bring the matter before a different court.
She also said the relatives of the Omagh victims had been misinformed by theauthorities.
Detectives in Dublin and Belfast tonight said the conviction was a shattering blow to the Real IRA, while relatives of the Omagh bombing insisted the verdict would strengthen their stg£10 million civil action against McKevitt and four other men they blame for the atrocity.
The officer who headed the investigation against McKevitt, Chief Supt Martin described the verdict as "a significant conviction".
"I would hope the Omagh families can take some measure of comfort from this particular prosecution."
But Mr McKevitt was not convicted of involvement in the bombing and no-one has been charged with the attack. However, families' of the victims insisted the conviction was a major step in their fight for justice.
Mr Michael Gallagher, whose 21-year-old son Aiden was killed in Omagh, expressed dismay that the charges did not cover the atrocity.
"I am very bitter, very disappointed. There is no doubt that this man, who was the senior member of the Real IRA, had responsibility," Mr Gallagher said.
But Mr Stanley McCombe, whose wife Ann died in the explosion, said: "The net is closing in on the Omagh bombers ... Having come this far, we cannot let them get away."
A hardline republican paramilitary since the 1970s, he was once an associate of Sinn Fein leaders Gerry Adams and Martin McGuinness, before he defected to the Real IRA after the advent of the peace process.
McKevitt's wife Bernadette, the sister of hunger striker Bobby Sands, who was in court right up until her husband dismissed his defence barristers, was also absent for the judgment.
Despite the significance of the conviction Chief Supt Callinan said: "There remains within this jurisdiction groups who are hell-bent on attacking democratic principles."
additional reporting agnecies