Tanaiste Eamon Gilmore says the loyalist violence over the flag protests was being organised by "known criminals".
The Tanaiste said the violence was being orchestrated and "those behind it are known criminals, intent on creating chaos".
Mr Gilmore said the violence has "got to stop". He said the vast majority of people on both sides of the Border wanted the Good Friday Agreement to succeed and the progress to date to be built upon.
The Tanaiste spoke with the Northern Secretary and leaders of the political parties in recent days.
Mr Kenny said the governments were attempting to deal with "diverse groups".
"The problem in the North is a wider failure of politics. The dominant parties in the Northern Executive have failed to demonstrate that democratic politics works.
"When politics is not about the economy and improving people's standard of life, it reverts to being about parades, flags and division," he said.