North reaction: A considered Sinn Féin response to the arrests may come from the party president, Mr Gerry Adams, tomorrow.
Mr Adams is due in Strabane, Co Tyrone, in the afternoon for a commemoration for three IRA men in the town, at which he is to deliver an address.
Yesterday the party's chief negotiator, Mr Martin McGuinness, took a cautious approach to the arrests and the break-up of an apparent massive money-laundering operation.
Mr McGuinness said: "I haven't heard anything that would make me change my assessment, but that doesn't mean we won't reflect on events as they unfold.
"I don't know what the implications are. I certainly am not going to rush to judgment. I want to hear the full facts of what we're dealing with at the moment."
The SDLP, which is standing by its policy of seeking the inclusion of all parties in the political process, accused republicans of lying and deceit.
Speaking from the US, the party leader, Mr Mark Durkan, said: "The picture emerging vindicates our stated view that the Provisional movement is running a very structured criminal enterprise.
"They are filling their coffers from racketeering, smuggling and money-laundering.
"These money crimes have been perpetrated using the resource of a private army. They have used everything from threats to kidnapping families and even murder in the course of robberies."
Accusing the movement of using democratic support as cover for criminality, Mr Durkan continued: "Some have suggested that Sinn Féin should sever its links with the IRA. But, for example, Sinn Féin's Pat Doherty already denies that there is a relationship between them, so we have already had that line. Few would believe that such a split would be anything more than a divorce of convenience.
"All of us have been asked to make a huge leap of faith for Sinn Féin in recent years. Don't now ask us to make a huge leap of fiction."
Unionists are increasing pressure on the Northern Secretary to levy severe sanctions on Sinn Féin elected representatives and to exclude them from the political process.
They are calling for a statement to the House of Commons on Tuesday by the Northern Secretary, Mr Paul Murphy, to mark a distinct toughening of the British stance against Sinn Féin and the IRA.
A senior UUP member and close Trimble aide, Mr Michael McGimpsey, said: "It appears that it is business as usual for the IRA. This whole affair has shown what little respect the republican movement has for democracy."
The DUP commended the Garda for its success and said the capture of so much cash illustrated the scale and the "vast nature of the Provos' criminal empire".
Mr Jeffrey Donaldson, the Lagan Valley MP, said: "Murder and robbery are the trademarks of the Sinn Féin-IRA machine. Yet, despite the fact that the IRA have such a track record, the prevaricating and deceit continue."
Directing remarks at the British Prime Minister and the Northern Secretary, he added: "It is crunch time for the Government.
" They must begin to take steps to put the Provos out of business. The IRA are an impediment to peace."