Dos Santos who served in the last Socialist government, led by José Sócrates, was speaking in a break from the conference on competitiveness organised by the Porto Business School in Lisbon.

“It is difficult to understand” he said that an entity such as the commission that was part of the ‘troika’ of international institutions that oversaw Portugal's euro-zone bailout and “so praised the effort that the country made to correct” its financial situation could tae such a step.

“I think it is very difficult to explain to the Portuguese who suffered throughout these years from the effects of that adjustment [the reason why it] now imposes a fine," dos Santos argued.

Such a move - even if called for under euro-zone rules - "ends up having a very negative political connotation” because it might imply a negative judgment on the policies now being followed by a new Socialist government.

"We don't yet have sufficient results to assess the way that the economy and finances both private and public have reacted to the political framework in which the country has been living," dos Santos said in a reference to the minority Socialist government that has been in power since November thanks to support in parliament from other left-of-centre parties. "We need to give it some time."

It was the last Socialist government formally sought a bailout while in a caretaker capacity after losing the 2011 general election but its right-of-centre successor that implemented the resulting adjustment programme.

“I think that the European authorities in delicate situations have shown a capacity for good sense," dos Santos concluded. "I hope that once more that capacity will be there."

The European Commission last month proposed that excessive deficit proceedings be opened against Portugal and Spain, because of their public sector budget deficits being more than 3% of gross domestic product. It said that they should be given “one more year, and only one more year” to narrow their deficit to meet the euro-zone rule.

In making its decision it said it “too into account the current point in the economic cycle”, in which it is necessary to send signs ”of respect for the rules”, but also “support to the economy”, with a view to growth recovering.

The final decision on whether fines are to be imposed - which could also entail the suspension of EU subsidies - is to be taken by European Union finance ministers at their meeting in July, after the general election in Spain.