SDLP leader Colum Eastwood has said he will not attend White House celebrations on St Patrick's Day in protest at the US failure to call for a ceasefire in Gaza.
Mr Eastwood said close ties between Ireland and the United States placed an onus on Irish politicians to advocate for peace.
"It is because we are so close historically, diplomatically and, many of us personally, that we have a duty to be honest with our friends and allies - especially when we think they are wrong," he said.
Mr Eastwood added that the US had huge influence in the region and should use it to help deliver a ceasefire.
Speaking on RTÉ's Morning Ireland he said that there were more important things than raising money in America.
He said the conflict was unfolding in a fashion that was "catastrophic for the people of Palestine" and there was an opportunity here to make a point.
He said Sinn Féin can make their own decision on the matter.
"I just frankly think that some things are more important than raising money in America."
"I do not think either myself or Mary Lou McDonald will be able to make any kind of real protest by catching Joe Biden between pints of Guinness. I just do not think that is realistic...
"We are going to continue to engage obviously with Irish America, and people who are interested in the Irish issue, but given the fact that we are watching genocide unfold on our television screens every night of the week and the American administration has been totally weak in trying to stop it I just do not think it is appropriate for me.
"For me to go and drink Guinness and pretend everything is ok in the White House in that celebration. I just do not think that is the right thing to do."
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He said they will continue to engage with the American administration but added that it is more influential to take a stand at this point.
Mr Eastwood said the party would send a delegation which would meet with representatives of Irish Americans and Palestinian Americans to make the case for an end to violence.
He said they would use whatever influence they had to press for an immediate ceasefire in Gaza and the release of hostages held by Hamas.
Asked about Mr Eastwood's comments today, Green Party leader Eamon Ryan said it was more important than ever for the Irish Government to go abroad this year "to spread a message on our view on Gaza and other issues".
"That what's happening is unacceptable. There has to be a ceasefire now", he said.
"Why wouldn't we use the opportunity that goes with the stage we have on St Patrick's Day to get that message out? I think that's what we will and should do," Mr Ryan added.
Asked where he will be travelling himself on St Patrick's Day, he said that had not been fully agreed yet and he was awaiting sign off from the Department of Foreign Affairs.
Sinn Féin leader Mary Lou McDonald said she disagreed with the SDLP and said there is a lot of work done during the St Patrick's Day period in Washington.
Speaking to RTÉ's News at One, she said: "I believe there is a very important opportunity on this St Patrick's Day, of all St Patrick's Day, to bring a very clear message from Ireland to the United States in respect of Gaza, the West Bank, what has been happening in Palestine and to make that clear."
She said the US has been "on the wrong side of this for a very long time".
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Ms McDonald added that it is the Taoiseach who meets with the President and presents the shamrock.
Her comments come as Sinn Féin lodged a Dáil motion committing Ireland to join with South Africa in their case at the International Court of Justice.
The motion is to be debated tomorrow night.
Ms McDonald said: "I think the court has made its provisional ruling there is a plausible case here and I think the Government needs to act now."
Additional reporting Eleanor Burnhill
