Membership of a criminal gang should be made a crime, Labour leader Eamon Gilmore told the Dáil.
"The gardaí will then have a different basis on which to effectively pursue these gangs," he added.
Mr Gilmore also said that the witness protection scheme should be put on a statutory basis. It was known, he said, that there was a culture of intimidation and fear associated with criminal gangs.
"But it is not a new problem. They had to deal with this in the United States when they dealt with the Mafia. They had to deal with it in Italy when they had to deal with the Mafia."
He said there was no point in Taoiseach Bertie Ahern describing the problem after spending 10 years presiding over the current situation. "We need to have some sense of what the solution is."
Mr Gilmore said the Taoiseach had presided over 140 gun murders, with convictions in only one out of six. "What are you actually going to do about it?" he asked.
Taoiseach Bertie Ahern said it was an unfortunate reality that in many cases associates of the crime victim would not co-operate with the gardaí.
Rejecting Mr Gilmore's demand for a statutory witness protection scheme, Mr Ahern said it was not believed that this would be of help.
Mr Ahern referred to progress made in tackling crime but said that there was a difficulty relating to gun crime. He claimed that he would not be supported by Mr Gilmore if he introduced measures similar to those operated in the United States.
He said the witness protection scheme was 10 years in existence. A review of the scheme had been completed just short of two years ago. "As recently as yesterday, it was looked at again."
Earlier, Fine Gael leader Enda Kenny said that a question needed to be asked about the "great disconnect between crime Ireland and the Ireland of the law-abiding citizen".
Ten years ago, 38 murders had been recorded. They were not gangland hits, and 34 were solved. "Ten years on, the detection for gun crime is now 16 per cent. This year so far, 14 gangland killings have occurred. Firearms offences have rocketed by 600 per cent."
The question that needed to be asked was whether the "Government or the gunmen" were in charge of the streets. Fine Gael would support the Government in measures on gangland crime, Mr Kenny said.
