EU leaders meeting in Brussels have agreed a "period of reflection" on the constitution amid fears that a knock-on effect would mean the document would be rejected in countries still planning to have referendums.
Governments are to come together in one year, under the Austrian EU presidency, to take stock of the situation.
However, they stressed that the constitution itself will not be renegotiated and that ratification will continue.
Announcing the decision, Luxembourg prime minister and current head of the EU Jean-Claude Juncker said "we all believe that the constitution is the right answer to the many questions of the European people.
"We believe ratification must continue".
But it will be up to national governments when to ratify and how - with the process not likely to be ended before mid-2007, according to Mr Juncker.
The current deadline of end of October 2006 "is no longer tenable" said the prime minister who stressed that countries that want to ratify the document via their parliaments may do so while member states planning to have referendums "will decide autonomously when those referendums are to be organised".
Luxembourg under the spotlight
As the next country to have a referendum, on 10 July, Luxembourg comes under the immediate spotlight.
But it is not up to Mr Juncker to postpone the planned referendum - with recent polls showing the No side gaining ground - as this has to be decided by the country's parliament.
Luxembourg MPs must "decide if further debate is required" said Mr Juncker adding that he cannot "prejudge" their decision.
Other countries have already indicated that they will postpone their decision - effectively putting ratification on ice.
Denmark's Anders Fogh Rasmussen said that his country's referendum, planned for 27 September, will be postponed until there is more "clarity" but did not set a new date.
Meanwhile, an Irish government spokesperson indicated that Dublin is also considering postponing its referendum, which had been set to take place in the autumn.
The UK had put it referendum plans on ice already while the Czech Republic and Portugal are planning to.
Only Poland has committed itself to pressing ahead with a referendum on 9 October.
So far, ten countries have ratified the constitution, two have rejected it - France and the Netherlands - and 13 still have yet to ratify it.
Referring to the French and Dutch No, Mr Juncker said "I really believe neither the French nor the Dutch rejected the constitutional treaty", adding that "unfortunately, the electorate did not realise that the constitutional treaty was specifically aimed at meeting their concerns and that's why we need to have a period of explanation to explain this to our citizens".
Europe will not stop
Legally, the constitution can only come into force if all 25 member states have ratified it - meaning that Paris and The Hague would have to put the document to their people once more.
While the rejections in both countries are still too fresh, there could be a possibility to put it to another referendum in France after the 2007 elections, when there may be a new French leader.
But Mr Juncker denied that this thought had figured when he mentioned that ratification wil take at least until mid-2007.
European commission president Jose Manuel Barroso said "Europe's not going to stop" adding that "the EU has to meet citizens' expectations in Europe".
By: N. Peter Kramer
