People leaving or entering the European Union will have to declare cash totalling 10,000 euros ($13,300) or more under new rules from Friday aimed at cracking down on money laundering.
Up to now, national border authorities among the 27 EU members enforce their own restrictions on the amounts they allow individuals to bring into their countries.
The new rules will introduce a common EU-wide approach from Friday and customs officials will be empowered to seize cash in excess of 10,000 euros until a valid reason is given by a traveller for carrying such large sums.
"The customs will hold the money if they find it has not been declared," said Maria Assimakopoulou, spokeswoman for EU Tax and Customs Commissioner Lazslo Kovacs.
Travellers have found ingenious ways of carrying large sums around the EU. Germany last year confiscated 60 million euros from people entering from non-EU member Switzerland alone.
"We had one woman who had rolls of cash stuffed inside her walking stick," an EU Commission official told reporters.
The new rules complement separate EU regulations that monitor transactions made through credit and financial institutions.
The requirement from Friday applies to all currencies for sums worth 10,000 euros or more.
The Commission official said customs authorities would also question people whom they find regularly carrying in and out of the EU large sums of money, despite coming under the 10,000 euro threshold each time.
EU countries will continue to have their own different, nationally imposed thresholds on how much cash travellers can carry between member states.