FIVE European countries may seek to follow Britain’s lead in leaving the EU in a Brexit domino effect, Germany has warned.
France, the Netherlands, Austria, Finland and Hungary could leave.
Front National leader Marine Le Pen has pledged to hold a French referendum if she emerges victorious in next year's presidential elections.
While for the past two months a Nexit has been on the cards after Dutch voters overwhelmingly rejected a Ukraine-European Union treaty
Details of Berlin's concerns were outlined in a finance ministry strategy document.
Angela Merkel's country faces having to pay an extra £2.44billion a year to the annual EU budget once Britain has left.
Fears for the future of the EU have prompted German government officials to propose that Britain is offered “constructive exit negotiations”.
The aim is of making the UK an “associated partner country” of the EU, according to German newspaper Die Welt today.
Hungarian Prime Minister, Viktor Orban, warned that Europe needs to change its ways.
“Brussels must hear the voice of the people, this is the biggest lesson from this decision," he told public radio.
“But Europe is strong only if it can give answers to major issues such as immigration that would strengthen Europe itself and not weaken it. The EU failed to give these answers."
“The conclusion is obvious. We need a new European treaty," said Jaroslaw Kaczynski, who heads the Law and Justice party.
“We need a positive reaction, and not persistent movement in the same direction, a direction which has led to crisis," he added.
Marine Le Pen, leader of Front National
There is no point beating about the bush: today is a watershed for Europe
Tensions are rising across the EU, with Denmark, France, Italy, the Netherlands, and Sweden all facing demands for referendums over Europe.
In a statement, German Chancellor Angela Merkel said: "There is no point beating about the bush: today is a watershed for Europe, it is a watershed for the European unification process."
The European Commission president, Jean-Claude Juncker, has said this does not spell the end of the European Union and the bloc has “decades of experience in overcoming crises”.
The Brexit vote is expected to encourage populist parties in Europe to seek similar referendums for their nations.
Foreign ministers of the founding EU states are meeting in Berlin today to try to revive the shattered confidence in the European Union.
The German Foreign Minister Frank Walter Steinmeier, said: “We cannot rush into hectic activity, pretending we have all the answers, but after the British decision we also cannot fall into depression and inactivity.”