Responding to suggestions both from Germany and the Netherlands that countries that do not adhere to strict budget discipline be required to dump the euro, EU economy spokesman Amadeu Altafaj-Tardio on Thursday insisted that there is no debate happening at any level on whether Greece should be kicked out.

"There is no discussion whatsoever on such an eventuality," he told reporters in Brussels.

"Neither exit nor expulsion from the euro area is possible, according to the Lisbon treaty under which participation in the euro area is irrevocable," he added, referring to the European Union’s rule-book.

Earlier the same day, the Dutch prime minister, his economy, finance and foreign ministers outlined proposals for the creation of a specially appointed European commissioner who would be given the power to take over the economy of heavily indebted member states and ultimately kick a state out of the euro.

The same day, German finance minister Wolfgang Schaeuble told Deutschlandfunk radio that the Greek people must decide whether they want to stay members of the currency union.

"I understand that there is resistance among the Greek population to austerity measures," he said. "But in the end it is up to Greece as to whether it can fulfil the conditions that are necessary for a membership of the common currency."

Despite the commission's insistence that withdrawal or expulsion from the euro is not legally possible, the Lisbon Treaty did for the first time introduce a clause describing exit from the European Union itself.

"Any member state may decide to withdraw from the Union in accordance with its own constitutional requirements," article 50 of the text says, going to describe the mechanics of such a move.

In 2009, the European Central Bank produced a legal working paper examining the legal issues surrounding euro and EU exit.

It concluded that euro exit is only possible upon exit from the union as a whole.

"A member state’s exit from European monetary union [EMU], without a parallel withdrawal from the EU would be legally impossible," the paper said regarding a country deciding to exit itself.

But there is a slight nuance to the question of whether a country can be kicked out against its will, noting that this is "next to impossible".

"A member state's expulsion from the EU or EMU, would be legally next to impossible," the author wrote.

The paper goes on to say that expulsion, while "remote" is "still conceivable", however.

"The difficulties faced by some of them in steering clear of excessive budgetary deficits and in complying with their Stability and Growth Pact obligations at a time of acute financial crisis suggest that, however remote, the risk of a non-compliant member state being expelled from the EU or EMU is still conceivable."

Nevertheless, as there is no legal basis for this within the Lisbon Treaty, the paper concludes that while possible, the likelihood of such an event is next to nil.

"In the absence of an explicit treaty mechanism – expulsion from either the EU or EMU would be so challenging, conceptually, legally and practically, that its likelihood is close to zero."