SDLP leader Colum Eastwood has called on Secretary of State Theresa Villiers to declare any current or past beneficiary interest from offshore companies or offshore funds.
He made the call following the publication of papers from Panama law firm Mossack Fonseca which showed British Prime Minister David Cameron had £20,000 of shares in a company owned by his father.
Mr Eastwood, who is standing in the Foyle constituency, said: “The publication of the Panama Papers has shone a light into the grubby world of tax avoidance by a global financial elite.
“The revelations surrounding David Cameron’s own interests in offshore investment funds have dealt a hammer blow to his credibility, and that of his cabinet, on tax avoidance.
“This is a government which has taken an axe to public services and discarded any sense of social responsibility.
“They have pursued an agenda of punishing the most vulnerable, the least able to afford it, while a political and financial elite squirrelled away their considerable fortunes in tax havens.
“And remember, it is this cabinet of Tory millionaires that now has broad powers over support services and payments to some of the most vulnerable in our communities.
“These revelations underscore just how disastrous that decision was on the part of Sinn Féin and the DUP.
“Each and every member of the British cabinet should now come clean about any beneficiary interest they hold in offshore companies, offshore funds or offshore accounts.
“That includes Secretary of State Theresa Villiers who has watched, unmoved, as people in Northern Ireland bear the brunt of a Tory class war.”