The state-owned rail operator said on Thursday its three-times daily service, which promises to bring passengers the 640 kilometres from London to Frankfurt in about five hours, would not be in place before 2016. It had originally hoped to start running trains on the route for 2013.

Deutsche Bahn was initially due to receive 16 ICE trains worth a total of about 500 million euros and made by German engineering group Siemens (SIEGn.DE) in late 2011.

But technical problems have led to delays, and Siemens said on Wednesday it was now pushing back the delivery date beyond early December.

Eurostar, the operator of the Channel Tunnel passenger train service, is meanwhile also planning to start direct service from London to Frankfurt and Cologne in the coming years, once it receives its own order of trains from Siemens.

In addition to holding up plans for international expansion, the delay could cause disruptions to service in Germany during this year's busy Christmas travel season, Deutsche Bahn said.

"Our customers feel abandoned by Siemens. We had fully expected to have the trains up our sleeve when there are cancellations due to extreme weather conditions," Berthold Huber, chief of Deutsche Bahn's long-distance rail business, said in a statement.

"You have to remember that the trains were ordered in December 2008 and were initially promised for December of last year," he added. (Reporting by Maria Sheahan; Editing by Mike Nesbit)

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