Panamanian law firm Mossack Fonseca has informed customers of the impending media storm yet to be unleashed, as a leak of company information is scheduled to hit the headlines.

Mossack Fonseca – notorious for its indiscriminate assistance to the global rich and nefarious dictators – said its data had been leaked through an unauthorised breach of its server.

The company made Maltese headlines when its Maltese agent, the audit firm Nexia BT, used its services to open an offshore company for energy minister Konrad Mizzi.

The company, Hearnville Inc, was employed to hide Mizzi’s status as its beneficiary. The minister has since then declared that the company is owned by Orion Trustees of New Zealand, which manage a trust in New Zealand, whose beneficiaries are his wife and children.

The embarrassing revelations have put pressure on Mizzi to resign his post, but Prime Minister Joseph Muscat insists he knew of the New Zealand trust and Panama firm when he saw his minister’s draft declaration of assets.

Mizzi has submitted himself to an audit by the Commissioner for Inland Revenue, and an independent audit undertaken by a foreign audit firm. Muscat insists that Mizzi will not resign unless the Panama companies are found to have been used for tax avoidance, or other purposes.

In a letter to its customers, Mossack Fonseca’s marketing director Carlos Sousa-Lennox informed clients of a ‘Panama leaks’ story to unfold within the coming days.

Malta Independent columnist Daphne Caruana Galizia, who broke news of the Panama firm owned by Mizzi after the minister first only declared his New Zealand trust, published the letter Mosscak Fonseca sent to its clients and said the leaks involve hundreds of names of heads of state and ministers.

Konrad Mizzi only declared his beneficial ownership in Hearnville after it was revealed that he owned the Panamanian firm.

In February 2015, the International Consortium for Investigative Journalists revealed that over €607 million was kept by Maltese account holders in HSBC’s Swiss banking arm, to help them evade taxes at home.

Caruana Galizia’s son, data journalist Matthew Caruana Galizia, worked as a web application developer on the ICIJ’s Swiss Leaks project, which was described as the biggest banking leak in history, revealing the full scale of malpractice at HSBC’s Swiss subsidiary.