The Irish Cancer Society has said it will refuse corporate donations from the law firm acting for Japan Tobacco.
The charity said that it made a "difficult decision" to no longer accept any funding from Arthur Cox, the firm representing the tobacco giant in threatened court action against plans for plain cigarette packs.
The charity received €20,000 in both 2013 and 2014 from Arthur Cox, which is also a legal adviser to the HSE.
Mark Mellett, a spokesperson for the Irish Cancer Society said that they made the decision after the "aggressive action" which claims the new law is in breach of their intellectual property rights.
"Arthur Cox are leading a legal action against the legislation for plain packaging on behalf of Japan Tobacco Ireland," said Mr Mellett.
"We will be declining further donations from Arthur Cox. In light of the aggressive action, we feel we have to take this measure.
"Over 92pc of income comes from individuals and companies so it was a difficult decision to make," Mr Mellett added.
John Player, which is part of the Imperial Tobacco Group, and Japan Tobacco Ireland has said it would bring the Government to the High Court if it did not abandon plans to introduce plain packaging for cigarettes.
The companies claim the new law is a breach of their intellectual property rights and will lead to an increase in cigarette smuggling.
Children's Minister James Reilly said earlier this week that it was not appropriate for legal firm Arthur Cox to represent tobacco firms and State agencies under the aegis of his department.
Mr Reilly said he has a "problem" with Arthur Cox continuing to provide legal advice to the HSE if it is representing tobacco firms, which he said put the lives of people at risk.
"I am very concerned about a perceived or real conflict of interest here of legal firms representing both sides in a hugely high stakes situation like this," Mr Reilly added.
"We are fighting for the future of our children and the health of our nation against the determination of Imperial Tobacco and Japan Tobacco International to increase their profits at the cost of people's health in this country."
"I fail to see how we send the right message by employing legal firms that are prepared to represent the tobacco industry," the minister added.
"Their inability to come out and tell the truth time after time has been quite shocking frankly and we are going to stand firm against them."