Costa was speaking to journalists after attending the inauguration of new buildings and laboratories at Hovine, a Portuguese multinational in Loures, after he was questioned about the 'Luanda Leaks' revelations about dos Santos's business dealings.

"It is up to Portugal to collaborate fully with the Angolan authorities, as we have been doing and as we will do," Costa said. "I hope that this case will allow Angolan justice to deal with what it has to deal with and for Portuguese companies to continue to develop their activity within the framework of the greatest possible stability."

Asked about the fact that dos Santos has major stakes in several large Portuguese companies, Costa sought to draw a line between the issue of her as an investor in these companies and their business activities.

"I don't know the details of the court cases, but the investigation has been about a shareholder and not about the companies," he stressed. "Therefore, the measures that are adopted in relation to the shareholder will not necessarily affect the companies.

"Companies have a distinction between what are their [share] capital, their resources, and what are the capital and resources of their shareholders," he concluded.