Janice Smyth was speaking from the union's conference in Liverpool, where members voted overwhelmingly in favour of a "summer of protest".
She said nurses in Northern Ireland are paid "less than anywhere in the UK".
The RCN is calling on the next government to end years of below inflation pay rises.
A consultative ballot of members of the Royal College of Nursing showed that a majority were in favour of strike action - but the turnout was too low for a formal ballot to be held.
Janice Smyth said the pay issue needed to be addressed: "Nurses in Northern Ireland have had no decision this year, about even the 1%.
"It is devastating. Nurses feel nobody is listening to them, they don't have enough staff to look after their patients, that their own health and wellbeing is being affected and they can't pay their bills.
"It is a dire situation and they have had enough.  They want something done about it."
The RCN has warned the government that it will launch a formal ballot on strike action this year unless the 1% pay cap is lifted. Janice Smyth told the BBC this was a red line for the union.
"It is the least that members will accept. If the governments across the four countries don't do something about nurses pay it is inevitable our members will be balloted later this year."
The Northern Ireland director of the RCN (Royal College of Nursing), has said nurses have "had enough" of below inflation pay rises.