Sinn Féin leader Mary Lou McDonald says support for a united Ireland is 'strong' across corporate America.
She was responding to questions regarding party fundraising in the United States.
Asked by Newstalk Breakfast host Shane Coleman about raising funds abroad, Ms McDonald says it is all done fairly.
"We don't run policy on the basis of favouring the few - we do not favour, nor do we participate in, policies that are about looking after big developers, landlords or cuckoo funds or vulture funds.
"That's the track record in respect of housing.
"We accept donations on the same basis as any other political organisation within the rules of law and within the regulations.
"All of that is regulated, accounted for and fully reported."
And she says all money which is raised in the US goes specifically towards Irish reunification.
"The money that's donated in the [United] States is very explicitly on the basis of support for Irish reunification - which is really strong - not just in corporate America, although it's strong there, but right across the trade union movement and community and right across Irish-America.
"The money that's raised in the States, there are very, very strict regulations as to how that money can be expended.
"And it doesn't come home to Ireland because that would be illegal in terms of this jurisdiction.
"It is used for lobbying, for building support and understanding for the peace process.
"And we saw, I think in very recent times with the whole Brexit and protocol debacle just how pivotal the support and understanding of the United States and key players were.
"It's used for those purposes, and of course, people are entitled to fundraise but we all have to respect the law".
Earlier this year, adverts appeared in a number of prominent US publications promoting a united Ireland.
The 'Friends of Sinn Féin' group organised the pieces in The New York Times and Washington Post.
The ads called for a date to be set for a referendum on a united Ireland.
They said the Good Friday Agreement "replaced conflict and violence with a peaceful and democratic pathway to a united Ireland."
They said the unionist electoral majority in the North "is gone" and that "a new Ireland is emerging".
"A new Ireland that is seeking to undo the damage of the undemocratic position of Ireland 100 years ago and the recent British government imposed Brexit.
"We appeal to the Irish Government to promote and plan for unity", they added.